Ask MetaFilter questions tagged with math
http://ask.metafilter.com/tags/math
Questions tagged with 'math' at Ask MetaFilter.Tue, 25 Aug 2015 22:59:05 -0800Tue, 25 Aug 2015 22:59:05 -0800en-ushttp://blogs.law.harvard.edu/tech/rss60Typer Shark for Algebra?
http://ask.metafilter.com/284894/Typer%2DShark%2Dfor%2DAlgebra
I want to take a pre-calculus class, but I’m not prepared.
I would find it easier to prepare with some kind of program or system to refresh my math skills and learn some of what I missed in high school. I, like most mammals, am motivated by immediate rewards. Is there an online game where the math gets progressively harder and you earn rewards for completing problem sets? I was more willing to practice typing when I was defeating sharks than when I worked from a book. Does such a gamified system exist for math? I have a bachelor’s degree in International Relations, which I managed to obtain without taking much real math. I’m now trying to position myself to make a career change into a science-based field, and the linchpin in getting to my other prerequisites is taking pre-calculus, but since I only took statistics and formal logic in college, I need to place into pre-calculus (or take some lower level prerequisites). <br>
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More than 18 months ago, I said I was going to do some independent studying to get myself up to speed to place into pre-calc. I did really well for about six weeks, then totally lost momentum. I've heard of Khan Academy - though I admit I haven't spent any time on there - and I have Saxon’s Algebra I and Algebra II books. I made it about ⅓ of the way into Algebra I, but haven’t touched it since May 2014.<br>
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I’d also love to hear from others who, like me, needed to bulk up your math skills in your late twenties/early thirties. What worked for you? Am I best off just signing up for the lower level algebra course I’m likely to place into now, knowing I’ll then be ready for pre-calc in a couple of quarters? In a related topic, I'm also willing to hear advice for maintaining motivation on a long-term project you want to complete but are having trouble staying focused on.<br>
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Some similarities to <a href="http://ask.metafilter.com/113970/Math-basics-need-be-strengthening">this</a> question, though I’m starting from a much lower level, and maybe some to <a href="http://ask.metafilter.com/187878/If-an-geeky-child-is-traveling-South-at-839-MPH-and-his-nerdy-dad-is-going-North-at">this</a> one, though I'm pretty focused on algebra and these answers appear more scattershot.tag:ask.metafilter.com,2015:site.284894Tue, 25 Aug 2015 22:59:05 -0800CatenationHow to Math
http://ask.metafilter.com/284341/How%2Dto%2DMath
I'm a computer science major in college. I'm not a freakin' genius, but I do well-- get A's in my classes, good with abstraction (e.g. pointers), etc. However, I seem to have missed... my entire high school pre-Calculus math curriculum? I don't know. I've never gotten less than an A in a math class, but mathematical notation and reasoning just do not stick with me. I can't really explain it, but I'm good at tests, not so good at creative mathematical thinking. Would do poorly on the Putnam. It's a huge hole in my self-esteem and I really want to change this. <br>
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Tiny example: During a programming class, an instructor scribbles down a formula involving factorials. I stare at the board and try to remember how factorials work, even though I aced my Honors Analysis course (which was mostly proof writing). It's like I have to learn everything from first principles to remember any of it.<br>
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Further examples are hard to come by as it mostly relates precisely to things I can't remember or explain. I've never taken a class on probability and subsequently I absolutely hate it, because it seems like mostly arcane formulae and non-intuitive reasoning about weird, hypothetical events. Combinatorics is another important field that I suck at. I wouldn't say I'm super skilled at Calculus, but I had very little trouble in my Calc class since by the time I took Calc I was actively interested in math and soaked it up better, and the principles of real numbers are familiar. (I have a feeling most of this lack of proficiency comes from not being a natural math whiz and having a rather poor high school math/science education. I'm self-taught at most things, but math wasn't my focus or main talent in high school.)<br>
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I recently took the GRE and studied a lot (well, moderately-a lot) for the math section and did not do all that stellar (78th percentile). Sad! But it highlighted my weaknesses-- data analysis is easy but sometimes I go too fast and make dumb errors, I have no fucking idea how probability/combinatorics work, even ALGEBRA eludes my slippery grasp when I'm making dumb leaps of logic. <br>
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Is there just like, a GREAT book for hammering down these kinds of concepts that I should obviously have under my belt by now? I know what it feels like to be the smart kid in the class-- not necessarily the superior intellect but the one that just has the hang of things-- and I want to be that, now, for math. Pretty soon I'm going to be facing more discrete math and algorithms classes and I want to be better prepared.<br>
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Note: Also coming in to play is the fact that I'm female and so I constantly have this voice in the back of my head saying "why are you such a STUPID GIRL why are you such a MATH IS HARD BARBIE DOLL" and it's driving me crazytag:ask.metafilter.com,2015:site.284341Fri, 14 Aug 2015 07:10:47 -0800AnonymousLearning To Read Mathematical Notation?
http://ask.metafilter.com/284277/Learning%2DTo%2DRead%2DMathematical%2DNotation
I do not have a math background, but I have been learning statistics for work and while I understand the concepts, I am having a really hard time reading mathematical notation (proofs, formulas, etc). It feels like I missed the 101 class in reading the language of mathematics.
Are there particularly good resources out there on reading Mathematical Notation?tag:ask.metafilter.com,2015:site.284277Wed, 12 Aug 2015 13:42:44 -0800SpuriousFano Plane and Hexagonal Tiling - a deep connection or a shallow one?
http://ask.metafilter.com/284199/Fano%2DPlane%2Dand%2DHexagonal%2DTiling%2Da%2Ddeep%2Dconnection%2Dor%2Da%2Dshallow%2Done
I've been chewing on the <a href="https://en.wikipedia.org/wiki/Fano_plane">Fano plane</a> a lot these last few weeks, and have just noticed something that seems really interesting to me. Notably, that the <a href="https://dl.dropboxusercontent.com/u/381295/FanoHex/fanocolors.png">seven lines</a> of the plane <a href="https://dl.dropboxusercontent.com/u/381295/FanoHex/FanoHexTiles.png">map very nicely</a> to the 7-color hexagonal tiling. Is there some trivial mathematical reason why this will naturally be the case, or is there a more profound connection between these two things? Have I somehow stumbled across something new? Googling has offered me no obvious answers (and in fact, has also not shown any images of Fano planes using my coloring scheme, mapping the 3-bit numbering of points to RGB coloration). If I'm treading familiar ground, is there somewhere I can learn more about this connection? If I'm in undiscovered territory... where do I go from here?tag:ask.metafilter.com,2015:site.284199Tue, 11 Aug 2015 01:24:24 -0800NMcCoyThe Best Historical, Educational, or Informational YouTube Channels?
http://ask.metafilter.com/283069/The%2DBest%2DHistorical%2DEducational%2Dor%2DInformational%2DYouTube%2DChannels
I'm looking for YouTube channels that are dedicated to providing education about or insight into interesting subjects. They can have humor in them, but I'd prefer for them to be primarily informative rather than humorous. As YouTube content providers become more and more sophisticated, I've seen a huge influx of well-produced, interesting videos come out of individuals or teams of content creators. Some of these are more straightforward education, some are more entertaining. They fill the hole in my heart that The History Channel, The Learning Channel, Discovery Channel, etc. all filled in the 90s, and they generally come in small, snackable lengths with enthusiastic, interesting hosts or narrators - much as some of the information podcasts I listen to that have been talked about previously on Ask MeFi.<br>
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Some current favorites that fit into what I'm thinking about:<br>
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- Crash Course History/Astronomy/etc.<br>
- TED Ed<br>
- Atlas Obscura<br>
- Stan Winston School/Studio ADI/Steve Johnson FX/Legacy Effects<br>
- Chrontendo/Gaming Historian/Generation 16/DidYouKnowGaming<br>
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I've recently discovered that PBS has a series of really interesting seeming channels (The Art Assignment, Blank on Blank, BrainCraft, Deep Look, PBS Space Time, PBS Idea Channel, and semi-comedic shows like Dr. Frankenstein, MD - none of which I've delved into too much so would like suggestions to weed out the good ones), and I'm wondering how much more is out there. Is the new Bill Nye or Alton Brown a 22 year old on YouTube? Science, philosophy, engineering, history, pop culture, hobbysits, mathematics, tech, news - any subject or focus is fair game. I just want to learn!tag:ask.metafilter.com,2015:site.283069Fri, 17 Jul 2015 16:45:21 -0800gregorygHow to self-study science from textbooks like a boss?
http://ask.metafilter.com/282959/How%2Dto%2Dself%2Dstudy%2Dscience%2Dfrom%2Dtextbooks%2Dlike%2Da%2Dboss
I'm an (older) grad student doing research in applied physics. I've ticked all my class requirements but have a shortlist of subjects I feel would be useful to my research and my career. I've translated these into a list of reputable, recommended textbooks to read.
I've started reading those, usually in the evenings after all daily tasks are complete, and I enjoy it very much - but does anyone have tips to maximize the payoff of those reading hours? Some extra points:<br>
- I want to keep this learning "pleasurable" - for example I wouldn't like taking detailed notes<br>
- I've so far skipped all problems but am considering reading the books entirely once, then going through them once more to solve a few problems from each chapter<br>
- I'm looking to get the "big picture", not to grasp all the details - if I ever need them I can come back to the books later on<br>
- I don't annotate or even know how to. I've tried doing it but never got anything out of it.<br>
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Thanks so much everyone!!!tag:ask.metafilter.com,2015:site.282959Wed, 15 Jul 2015 13:55:31 -0800RitonMore self-confidence for approaching games and puzzles
http://ask.metafilter.com/282389/More%2Dself%2Dconfidence%2Dfor%2Dapproaching%2Dgames%2Dand%2Dpuzzles
I've reached the proverbial straw moment where I'm realizing that, approaching any sort of numbers/critical thinking game or challenge that is meant to be fun, is instead filling me with absolute dread. I find myself becoming incredibly tense and anxious, and very often preemptively angry at myself for OF COURSE being too stupid to pick it up, which means that often I don't even try to pick it up, which then becomes an inescapable feedback loop. I need to change this, please tell me how! I was raised in a "Get this right immediately or you're a complete failure" environment, which clearly haunts me to this day. As soon as I was able to escape into the arts at school I dove in head-first, and this meant that I was one of those girls who grew to hate math and thought most science too challenging to be truly enjoyable. I don't want to live the rest of my life like this.<br>
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This isn't a problem when it comes to playing competitive games - no problem losing to another person. It's more of the "See if you can figure out this thing with numbers/logic (oh woops the way it was set up was a trap too *wink*)" thing that kills me every time. Even with neat things that are meant to display how weird or finicky the human brain is my main takeaway is always "OH GOD I FAILED I DID IT WRONG."<br>
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What's the solution? What are the baby steps? What giant books of puzzles should I stash underneath my bed to do in the moonlight?<br>
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(I'm also married to a programmer who has no problem going "Huh, I got that wrong. Oh well! Let's try again" while I'm off whimpering in a corner hating myself. I want that confidence. ...Should I learn to code? Oh god.)tag:ask.metafilter.com,2015:site.282389Thu, 02 Jul 2015 16:01:03 -0800erratic meatsackHelp me create a player ranking system for a game
http://ask.metafilter.com/282247/Help%2Dme%2Dcreate%2Da%2Dplayer%2Dranking%2Dsystem%2Dfor%2Da%2Dgame
I want to create a ranking system for a game that will be more refined than just ranking the users in order 1, 2, 3, etc. I have a game, the participant number is variable and can go into the thousands. I already have a point system where I can rank them in order (1- however many participants there are, based on how many points they have obtained in the game). But ranking them 1, 2, 3, etc. is boring (and also communicates too much about how they are doing in relation to other players).<br>
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I want to instead create an artificial number for the ranking. So similar to a credit score, I want to take their actual ranking, do some math wizardry, and then tie it to a different number on a scale, similar to how a credit score can go from 300-850. Bonus points if you're able to give me some formula that lets me choose different ranges of numbers.tag:ask.metafilter.com,2015:site.282247Mon, 29 Jun 2015 21:03:24 -0800banishedMath equation problem
http://ask.metafilter.com/280732/Math%2Dequation%2Dproblem
Asking for a friend:
I have a question about how to work out a student's exam mark.
Unit 1 is worth 60%, Unit 2 is worth 40%. Both units are marked out of 80. For example, a student scores 67/80 on unit 1 and 69/80 on unit 2. What is their overall mark?
Thanks for any help!tag:ask.metafilter.com,2015:site.280732Thu, 28 May 2015 05:31:25 -0800charlenIs there a name for this shape?
http://ask.metafilter.com/280681/Is%2Dthere%2Da%2Dname%2Dfor%2Dthis%2Dshape
What would you call the shape of the two-dimensional outline of the two stones (cabochons)<a href="http://imgur.com/tyIYnbv"> circled in red in this picture</a>? The stones don't appear to be "perfect" but they are approximating something that I'm sure should have a name.<br>
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Just like I can tell that the outline of <a href="http://www.rpmjewellery.com.au/shop/product.php?productid=17585">this piece</a> is a <a href="http://en.wikipedia.org/wiki/Reuleaux_triangle">Reuleaux triangle</a>, I'd like to be able to name (and perhaps even mathematically generate) this curved parallelogram type shape.<br>
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The closest I've found is the shape formed by two sine waves that are out of phase like <a href="http://imgur.com/QHXFrBM">in this picture.</a>tag:ask.metafilter.com,2015:site.280681Wed, 27 May 2015 06:48:30 -0800sparklemotionMy Math/Excel Ignorance is Showing
http://ask.metafilter.com/279858/My%2DMath%2DExcel%2DIgonrance%2Dis%2DShowing
In three cells in a single column in Microsoft Excel, I'd like to be able to input a number in the bottom cell, have the middle cell calculate what a 6% sales tax on the figure below it is, and provide the amount before that 6% tax in the top cell.
Any help will be appreciated. The last math class I took was 44 years ago and I didn't pay much attention in that one.tag:ask.metafilter.com,2015:site.279858Fri, 08 May 2015 14:34:19 -0800imjustsayingAnything like the Harvard Extension School in the DC area?
http://ask.metafilter.com/279569/Anything%2Dlike%2Dthe%2DHarvard%2DExtension%2DSchool%2Din%2Dthe%2DDC%2Darea
I’m likely relocating to Washington DC this summer and I'm looking for somewhere where I can take Linear Algebra and a few other undergraduate math and statistics classes in Fall 2015 and Spring 2016 as a non-degree student. I currently live in Cambridge, and I've been taking courses through the (excellent) <a href="http://www.extension.harvard.edu/">Harvard Extension school</a>, which essentially offers open-enrolment versions of many of Harvard’s undergraduate courses. Unfortunately, they don't seem to have online versions of many of their advanced math courses, so I’m looking for an institution in DC where I can keep taking courses as a non-degree student as I apply for masters programs in Stats and CS.<br>
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Obviously there are many schools in DC, but from my limited googling it’s not clear to me which one is likely to offer the best options for someone in my shoes. If the instruction is good, I have nothing against night schools or community colleges, but I don't know which ones I should be looking at. I will have a very flexible work schedule, so taking courses during the day would also not be a problem. <br>
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Thanks in advance!tag:ask.metafilter.com,2015:site.279569Sat, 02 May 2015 12:29:07 -0800dyslexictravelerThe Mathematics Of Time
http://ask.metafilter.com/279238/The%2DMathematics%2DOf%2DTime
So I have a few years to kill and I'd like to spend them fully understanding what physicists and mathematicians know about time. I'm not looking for any sort of summary, I want to understand the math from the bottom up. I once caught my father going through the <em>Annus Mirabilis</em> papers with a red pen; that's the sort of proficiency I have in mind. Unfortunately my physics and calculus largely left off at the end of Freshman year, so I have a ways to go. I'm looking for some sort of hierarchy of the form:<br>
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In order to understand the math for Special Relativity you'll need to understand Z<br>
In order to understand Z you'll need to understand X and Y<br>
In order to understand X you'll need to understand U, V, W<br>
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Etc. I realize it's not as simple as a straight line, but that's the general idea.<br>
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I'd also like to find such a chart for the math that goes into Quantum Physics.tag:ask.metafilter.com,2015:site.279238Sat, 25 Apr 2015 17:57:26 -0800Tell Me No LiesAm I doing compound interest wrong?
http://ask.metafilter.com/279135/Am%2DI%2Ddoing%2Dcompound%2Dinterest%2Dwrong
I'm hoping Metafilter can help me with a stupid math question, but one that's bothering me about how I was taught to compound interest versus some numbers I'm reading/hearing online about a Supreme Court case. Here's the gist. I got lost in the Wikipedia mindhole this afternoon and ended up at <em><a href="https://en.wikipedia.org/wiki/United_States_v._Sioux_Nation_of_Indians">United States v. Sioux Nation of Indians</a></em> where I saw this:<br>
<blockquote>Finally, under its new authorizing statute, the Claims Court held the Sioux had suffered a taking cognizable under the Fifth Amendment, and were entitled to the value of the land as of the 1877 taking which was $17.1 million, the value of gold prospectors illegally took out of the land computed at $450,000, and 100 years' worth of interest at 5% per year which would be an additional $88 million.[18]</blockquote><br>
In my head, though, that number seemed...wrong. I was taught annual interest compounded with a formula of B_n = P*(1+i)^n. The balance at year n is the principal times 1+i to the n. So, I plugged into my calculator and I got that 100 years of 5% annual interest on ~$17.5 million is ~$2.3 billion including the principal. The only way I could get to ~$88 million of interest is ~37 years of compounding.<br>
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Can someone here help me? This is either an "I don't understand math" or "I can't read the court opinion" answer.tag:ask.metafilter.com,2015:site.279135Thu, 23 Apr 2015 10:07:15 -0800FortranExorcizing the devil from the details
http://ask.metafilter.com/279108/Exorcizing%2Dthe%2Ddevil%2Dfrom%2Dthe%2Ddetails
I'm currently studying undergraduate math and though the concepts are clear, I lose a lot of marks through carelessness or small errors. Please help me pick up on/avoid these better. I am sure I lack discipline. As a fairly bright sort I am accustomed to doing math in my head, which no longer cuts it at university level. Trying to hold it in my head for more involved problems results in small errors like losing a minus sign or slight number errors which throw the whole thing awry. I also have trouble mixing up capital and lower-case letters, which doesn't help.<br>
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The question is twofold: Faced with a similar detail-demanding discipline, what methods do you use to avoid errors? Similarly, how do you -find- errors after the fact?tag:ask.metafilter.com,2015:site.279108Wed, 22 Apr 2015 19:33:16 -0800solarionBusiness math word problem: calculating salary through "growth tiers"
http://ask.metafilter.com/279076/Business%2Dmath%2Dword%2Dproblem%2Dcalculating%2Dsalary%2Dthrough%2Dgrowth%2Dtiers
I'd like some help coming up with a formula for calculating annual salary increases. The idea is that a given job description will have two "growth tiers", through which an employee's salary will increase at different rates, and beyond which their salary cannot increase further (except for cost-of-living adjustment). There's also a "base growth factor", which is determined by individual employee performance--e.g. 10% for a stellar employee, 6% for a good employee, etc. Lots more inside. So here's an example: Let's say we have a Field Engineer, Amazing Ashley, who's currently making $63,000 (in 2015 U.S. dollars). The 2015 growth tiers for the Field Engineer position are the following:<br>
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$60,000: minimum salary<br>
$60,000 - $72,000: first, "quick" growth tier<br>
$72,001-$84,000: second, "slow" growth tier<br>
$84,001 and above is "maxed"--no further growth possible except cost-of-living adjustment<br>
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Ashley has done really well at her job in 2015, so in early 2016, at annual review time, she's assigned a "base growth factor" of 10%. Ashley's salary will be increased by the unmodified "base growth factor" until it hits the top of the first growth tier ($72K). It will then continue to increase through the second growth tier, but at a modified factor of 5% (half her base growth factor).<br>
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I also want to account for cost of living. Let's peg this at 1.7%. So Ashley's new 2016 salary would be something like (63000 + 6300) 1.017 = $70,478 (I think?).<br>
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Easy enough--because she hasn't crossed into the second growth tier yet. But the 2017 raise will be trickier. And here's the other thing: the growth tiers also adjust to account for increased cost of living. So while the 2015 tier caps for Field Engineer are $72,000 and $84,000, the 2016 numbers will be slightly more: $73,224 and $85,428.<br>
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Assuming Ashley continues to do amazingly at her job (10% base growth factor), what will her 2017 salary be? 2018? 2023?<br>
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And what about Decent Denise? (Sorry Denise.) She's a Field Engineer making $61,500 in 2015 who'll be given a base growth factor of 6% at her 2016 review, which means her new 2016 salary will be $66,298 (I think?). Assuming she remains merely decent, what is her 2020 salary?<br>
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So there you have it. I don't think I'm fully grasping the issue, so my presentation of the information might be bad and might be based on some wrong assumptions. There may also very well be "real" math/statistics terms for the concepts I'm describing, but I don't know them (which might be why I'm having trouble googling this one). If you know them, please set me straight.<br>
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Thanks in advance everyone!tag:ask.metafilter.com,2015:site.279076Wed, 22 Apr 2015 09:43:15 -0800Mr. ProfessionalBooks/review of high school math for former math major, current tutor
http://ask.metafilter.com/276837/Books%2Dreview%2Dof%2Dhigh%2Dschool%2Dmath%2Dfor%2Dformer%2Dmath%2Dmajor%2Dcurrent%2Dtutor
I need book recommendations two categories:
1) for myself for review (that are somewhere between high school text books and Spark notes)
2) just straight up textbooks for high school math (algebra i, geometry, algebra ii, trigonometry, pre-calculus) Hello! <br>
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Currently I tutor one student in Algebra ii. Although i have been able to eke it out, i would like a more comprehensive review of maths so i can do a better job. Part of the problem is my student doesnt have a text book and the teacher seems to randomly wander around in the algebra ii world. Another part of the problem is it has been many years since i have done math. The sad thing is, even though i have my undergraduate degree in math, so i really should be able to connect things better than i currently am, my brain has swiss-cheesed its math knowledge. I really like tutoring and i really like math, so i would like to tutor more. To do this, I need to do some serious review. I have been trying to do this, but i have run into a few problems:<br>
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Regarding review books:<br>
As i said, I need something between the high school textbooks and Spark notes. I really wish Spark notes were enough, but my brain apparently needs more help re-connecting concepts than those provide. I have gone to bookstores to check out their review books (___ for dummies, barrons, etc) for my student, and they seemed a little too long-winded for me (although if you guys recommend them, i will give them another shot)! I know it is whiny, but i get super bored trying to get myself to read about all this math targeted to current struggling high school students. I have tried to force myself to read, say, Barrons, but my brain revolts. I hope that makes sense.. Truthfully, i do not know exactly what i need/want, which i think is part of the problem. I can only really afford to buy one review book for each subject otherwise i would just buy a few books at barnes and noble and see which one works best (and I _have_ checked libraries and thrift stores and used bookstores for review books).<br>
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Regarding textbooks:<br>
I would really like to get one textbook of each subject, so i can see at what pace they teach concepts, have access to appropriate level problems, etc. I have checked many libraries, goodwills, salvation armies, misc thrift stores, the strand, and misc used bookstores and found 0 textbooks for my hours of looking. I know i can order them online through like amazon or a used textbook site, but the problem there is i dont know which books are good/bad and i dont want to have to buy a few books of each subject to find ones i am happy with. <br>
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On a side note, my brain has a really bad filter as to what things are more important than other things (i have add), which is why the seemingly easy task of choosing books is for difficult to me. Also, if you guys have any random advice you would like to impart to me, please feel free! Thank you guys for any help you provide and i hope this all made sense.tag:ask.metafilter.com,2015:site.276837Thu, 05 Mar 2015 15:31:15 -0800miss so and soLooking for a blogging platform that handles equations and code
http://ask.metafilter.com/276540/Looking%2Dfor%2Da%2Dblogging%2Dplatform%2Dthat%2Dhandles%2Dequations%2Dand%2Dcode
My friend and I are starting an academic blog. We will be posting equations and code snippets (mostly MATLAB), and are looking for a blogging platform that will allow us to enter them easily and display them nicely. Do you have any suggestions on what we should use?tag:ask.metafilter.com,2015:site.276540Fri, 27 Feb 2015 11:58:42 -0800tickingclockHow can I quantify these fitness scores?
http://ask.metafilter.com/276406/How%2Dcan%2DI%2Dquantify%2Dthese%2Dfitness%2Dscores
Hey math/fitness nerds. I'm working on a pet project. I'm trying to quantify general fitness levels across a population based on a few different scores. I have the tests, but need help setting up the values of each score. This question is not about the validity of these tests, it's about numbers. I'm open to discussion about the tests, but not here. (Please mail me if you have strong opinions about the tests.) This is strictly a math question.<br>
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I'm trying to give each score a value out of 100 so the scores can be displayed in a radar-style graph.<br>
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The tests are as follows:<br>
Overhead squat mobility test. Score from 1-5 points. (5 = 100%)<br>
1.5 mile run test time. 10 min 30s = 100% (630 seconds.)<br>
500 meter ergometer row test time. 1 min 37 s = 100% (97 seconds)<br>
1 Rep Max Deadlift. A weight of 1.75 bodyweight = 100%.<br>
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So here's an imaginary test subject:<br>
Male<br>
185 lbs<br>
Squat evaluation = 4/5<br>
1.5 mile run time = 12 minutes or 720 seconds.<br>
500 meter row time = 2 min or 120 seconds.<br>
1RM Deadlift = 225 lbs. At 185 lbs he'd need to pull 323.75 lbs.<br>
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So I'd like to know the best way to put each of the scores at a 100 point value. This is slightly tricky for me as obviously higher times would be worse than lower times.<br>
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Could someone help me with the formula in excel so I could just drop the scores into a spread sheet and get some answers? This is a basic math question not really an excel question. I know it's the sort of thing that's dead easy for some people but fairly mystifying for me.<br>
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To use the above examples:<br>
Goal time for 1.5 miles is 10 minutes and 30 seconds. (630 seconds.) The subject ran 1.5 miles in 720 seconds. How can I set up the formula so that 720 seconds is scored out of 100 on a scale that uses 630 as a perfect score of 100 with anything larger being a worse score?<br>
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Thanks.tag:ask.metafilter.com,2015:site.276406Wed, 25 Feb 2015 02:42:52 -0800TelfSomething more interesting than :(){ :|:& };:
http://ask.metafilter.com/276254/Something%2Dmore%2Dinteresting%2Dthan%2Dand
What are some fun, computationally intensive tasks for my new computer to do? I just got a new computer and I feel like making it work really hard. What are some things to do? Assume I can program, and that I can install most languages, libraries, and software packages (including MATLAB and Mathematica). 4 cores, NVIDIA GPU. I'm leaving this deliberately broad, but here are some loose criteria (all of which are optional):<br>
<br>
<ul> <br>
<li>doesn't require too much investment in specialist libraries or domains of knowledge</li><br>
<li>results are pretty, lots of colors</li><br>
<li>learning how to do it might be somewhat educational</li><br>
<li>if results not visual, they are interesting on their own terms</li><br>
</ul><br>
<br>
It has already occurred to me to draw a very, very high resolution picture of the Mandelbrot set, but I was hoping you all would have something more original. Do not limit yourself to rendering mathematically interesting bitmaps!tag:ask.metafilter.com,2015:site.276254Sat, 21 Feb 2015 15:15:26 -0800vogon_poetProbability distributions and their practical applications
http://ask.metafilter.com/276170/Probability%2Ddistributions%2Dand%2Dtheir%2Dpractical%2Dapplications
I am looking for a resource that lists probability distributions and their common real-world applications. For example, I'd expect to see: Lognormal - daily returns in the stock market. Poisson - failure rates for mechanical equipment, ... The closest I can find is this wiki entry. http://en.wikipedia.org/wiki/List_of_probability_distributions<br>
<br>
Ideally this would be a handbook which includes applications in as many fields as possible (biology, actuarial, physics, etc.) Does this resource exist?tag:ask.metafilter.com,2015:site.276170Thu, 19 Feb 2015 13:19:17 -0800wivyHelp me do some math?
http://ask.metafilter.com/275828/Help%2Dme%2Ddo%2Dsome%2Dmath
Help me do some math? I have four buckets. I need to fill each bucket with a certain number of widgets (no more, no less) from a pile. How many possible variations exist?<br>
<br>
BUCKET ONE:<br>
- Holds 4 widgets.<br>
- There are 4 widgets to choose from.<br>
<br>
BUCKET TWO:<br>
- Holds 3 widgets.<br>
- There are 7 widgets to choose from.<br>
<br>
BUCKET THREE:<br>
- Holds 4 widgets.<br>
- There are 13 widgets to choose from.<br>
<br>
BUCKET FOUR:<br>
- Holds 2 widgets.<br>
- There are 10 widgets to choose from.<br>
<br>
I'm sure I learned how to do this in school, but that knowledge has long since left my brain. If you could show me how you do the calculation in addition to giving the answer, I'd appreciate it!tag:ask.metafilter.com,2015:site.275828Thu, 12 Feb 2015 08:25:00 -0800NotMyselfRightNowKeeping on top of the snowstorm -- does it really matter?
http://ask.metafilter.com/275673/Keeping%2Don%2Dtop%2Dof%2Dthe%2Dsnowstorm%2Ddoes%2Dit%2Dreally%2Dmatter
I am in the snowy state of Massachusetts and avoiding my next foray out to shovel. Plus, spouse and I slightly disagree on how often we really need to go out and shovel. Does it really save time to shovel every few hours throughout the storm? I have a suspicion that it doesn't really save time, and that we be just as fine waiting until the end of the snowstorm -- is there a way to think this through mathematically to find a good answer?tag:ask.metafilter.com,2015:site.275673Mon, 09 Feb 2015 09:40:37 -0800lillygogGiant numbers (Ex: how many primes are smaller than the largest known?)
http://ask.metafilter.com/275591/Giant%2Dnumbers%2DEx%2Dhow%2Dmany%2Dprimes%2Dare%2Dsmaller%2Dthan%2Dthe%2Dlargest%2Dknown
Many sites say that the largest known prime is "2^57,885,161 − 1, a number with 17,425,170 digits." Given this and well known research about the density of primes, I think it's at least possible to estimate the number of primes between 1 and 2^57,885,161 − 1. But I don't know how to do this myself.
I really want the answer to this one (the order of magnitude at least), but I've got lots of these, and I'd ideally like more cool ones. :) For context, I'm making an activity for high school students in an afterschool math program. The activity is aimed at understating really big numbers, and this part of the program (4 sessions) is focused on bijections and infinties, with a theme of how mathematicians think about topics that are too large or abstract to handle with intuition, and for how mathematicians make choices that shape what the mathematics we study looks like. For this activity in the first session, in addition to many mathematical examples, I want to include some examples from life and things in the middle (like the limits of modern computation.)<br>
<br>
The activity is not to calculate these quantities, but rather to estimate them to the extent that they can be ordered least to greatest.<br>
<br>
I would greatly appreciate<br>
A) Suggestions for additions to this list<br>
B) Estimations for new additions or for the items listed below with question marks<br>
C) Corrections to this list if you think one of my listed estimations is at the wrong order of magnitude <br>
D) An estimate for the primes question in particular. <br>
<br>
THANKS!<br>
<br>
----------------------------------------------------------------<br>
<br>
The list so far:<br>
<br>
* The number of primes between 0 and 2^57,885,161 − 1<br>
* If two 'opponents' at Go are actually collaborating to make the game as long as possible, how many turns might the game last (on a 19x19 board)? (???)<br>
* The number of different chess games for which the board never returns to a previously experienced state. (???)<br>
* The approximate number of atoms in everything living on the earth (???)<br>
<br>
* The approximate circumference of the earth in miles (~10^4)<br>
* The approximate number of sheets of paper in a stack as tall as the height of the Transamerica Pyramid in SF (~10^6)<br>
* The approximate number of seconds in a human life (~10^9)<br>
* The approximate number of people in the world right now (~10^10)<br>
* The approximate number of neurons in a human brain (~10^11)<br>
* The approximate number of seconds between now and when a dinosaur last lived (~10^15)<br>
* The approximate number of ants in the world right now (~10^16)<br>
* The approximate number of calculations that can be done by the world's current fastest computer (The Tianhe-2 supercomputer) in 1 minute (~10^18)<br>
* The approximate number of stars in the universe (~10^30)<br>
* The approximate number of atoms in the earth and everything on it (~10^50)<br>
* The approximate number of different ways a deck of 52 cards might be shuffled (~10^68)<br>
* The approximate predicted number of atoms in the universe (~10^80)<br>
* The approximate number of rabbits that would exist in the universe after a year if, starting with 2 rabbits, ever day, every pair of rabbits alive mate and produce 6 offspring, and no rabbits ever die. (~10^219)tag:ask.metafilter.com,2015:site.275591Sat, 07 Feb 2015 05:40:29 -0800ch3coohDouble checking math for the gaslit
http://ask.metafilter.com/275560/Double%2Dchecking%2Dmath%2Dfor%2Dthe%2Dgaslit
A math problem followed by an issue with the boss. <br>
The math: my boss gives me 50 picomoles per microliter of human serum albumin as standard, with a molecular mass of about 66400 grams per mole. I loaded, as per his instructions, 100 microliters of that. I loaded 100 micrograms (in 100ul again) of keyhole limpet haemocyanin which has a molecular mass of 390000 grams per mole. Unless I'be goofed in the math, I loaded 332 micrograms (250 picomoles total) of HSA standard he ordered me to load. On the sample run, I loaded 100ug (39 picomoles total) of KLH. If that checks out with everyone else, awesome, please continue below and help me. If it doesn't then the following is still an issue but of a different flavor. <br>
<br>
So there was a problem with the equipment (sample loop on the HPLC) that caused the sample of KLH to be lost. My boss blows up at me and whether he was spitting because he was so worked up or because he was chewing again, it was still a sight this chemist wishes to never see again. He was angry because I had spent two days on the KLH sample and wasted it all (ignoring my feeble "but I saved 10ul for the mass spec analysis after this looked good by RP-HPLC!"), burning time, money (<$100), and used 300% of the HSA mass to boot. "Brainlessly" "thoughtless" "stupid" etc all made appearances here.<br>
<br>
But the math doesn't bear out, I used 1/3 the mass and was in no danger of overloading the column as he was going on about. It's a shame the sample was lost but I don't feel like there was any way for me to catch that before it happened. <br>
<br>
So the KLH is a side project that I'm doing while waiting for the real work to pick up again. I've also brought a second HPLC back from the dead, organized things in the lab, prepped for the real work starting up again next week, successfully explored a new method to augment the real work, and read whatever I could get my hands on about HPLC (which I had no direct experience in until three months ago, I was an Acta/FPLC guy and self taught this while waiting for the product rep to show up and give lessons, which never happened). I feel like in the three months I've worked here, I've done good stuff for someone who went from life science lab to a mass spec/organic lab. <br>
<br>
There has been one time when I did do something stupid (miscut a gel and let the labels on the tubes run off in the presence of acetone) and plenty of blowups over tiny things. Every time, he says something along the lines of, "I'm not angry just..." or "I'm not pissed with you but..." which is patently not the case. He was angry, that he calmed down 30s later while we were still talking isn't the same as not having exploded in the first place. He isn't always angry but that doesn't really matter when the stress from walking on eggshells around him accumulates. <br>
<br>
He is my point of contact here as a contractor but weirdly I was hired by another department to work for him. I'm around this other department, am invited and attend their lab meetings, and am on good terms with their boss (my actual boss?). So I want to send my angry point of contact a polite but firm letter addressing the math issue and how the stress stemming from his outbursts is not acceptable to me. I don't want to talk about it face to face at first as, well, I am not the strongest lily in the wilting lily garden, I would rather set the tone without having to be a strong confident speaker that doesn't get railroaded by outbursts and excuses. Would that work? Are there any other lines of approach people would suggest? If this doesn't get better, should I go talk to other-department boss, the budget of whom I fall under? <br>
<br>
I'm strangely not afraid, career wise. It's only been three months but I've self taught the industry standard instrument to what I think of as a remarkable degree (making my own programs that work, confirming separations by gel, optimizing purification). My current contract gives me two weeks pay on leaving (going to double check this in case things go way south way fast) and I live in the DC area, so a fair number of jobs for HPLC fluent life scientists. <br>
<br>
This is so weird for me. Thanks for the help in advance everyone!tag:ask.metafilter.com,2015:site.275560Fri, 06 Feb 2015 12:38:19 -0800Anonymous