Ask MetaFilter questions tagged with math
http://ask.metafilter.com/tags/math
Questions tagged with 'math' at Ask MetaFilter.Tue, 22 Jul 2014 18:07:45 -0800Tue, 22 Jul 2014 18:07:45 -0800en-ushttp://blogs.law.harvard.edu/tech/rss604x+y+2z=100, x>y, y>z, x+y+z=j, 3x+z=k, j>k, j+k=100.
http://ask.metafilter.com/265560/4xy2z100%2Dxy%2Dyz%2Dxyzj%2D3xzk%2Djk%2Djk100
4x+y+2z=100, x>y, y>z, x+y+z=j, 3x+z=k, j>k, j+k=100. WolframAlpha can only give me alternative forms or a solution involving 'real and imaginary parts of z'. Is there a solution I can count on my fingers? I wish to buy a thing. The thing I buy will have two desirable characteristics: j, and k.<br>
<br>
j comprises three sub-characteristics, while k comprises four sub-characteristics.<br>
<br>
I have three levels for ranking how important these sub-characteristics are to me - let's say 'super important', 'kinda important' and 'meh, whatever'. Obviously, they are of decreasing importance.<br>
<br>
I have rated the three sub-characteristics for j 'super important', 'kinda important' and 'meh, whatever'.<br>
<br>
I have rated three of the four sub-characteristics for k 'super important', and the fourth 'meh, whatever'.<br>
<br>
This means I have a total of four 'super important', one 'important', and two 'meh, whatevers'.<br>
<br>
Finally, j is a little bit more important to me than k. If further defining these variables help, then I think they'd be about a 60/40 split, though I'm flexible. They can be equal if that helps. At this stage I'd settle for k being less than j if it means a solution pops out.<br>
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I would like to assign positive numbers to x, y and z, because I'm a bureaucrat, that's why.<br>
<br>
So, <br>
<br>
x>y (must)<br>
y>z (must)<br>
<br>
j = x + y + z<br>
k = 3x + z<br>
4x + y + z = 100 (per cent)<br>
j + k = 100 (per cent)<br>
<br>
I can't change the number of characteristics, sub-characteristics, or levels of importance. <br>
<br>
I could make k=2x+y+z, and so change the overall equation to 3x+2y+2z, but I'm not smart enough to know if that helps. It didn't help WolframAlpha.</j>tag:ask.metafilter.com,2014:site.265560Tue, 22 Jul 2014 18:07:45 -0800obiwanwasabiMath Careers
http://ask.metafilter.com/265554/Math%2DCareers
Non-obvious careers for someone with a B.S. in Applied Mathematics? I just graduated with an Applied Mathematics major and Computer Science minor, and I need a job ASAP. The thing is, I didn't think too much about what I was going to do when I finished school. All the career advice I've seen for people with my degree falls in only a couple different categories, most of which aren't really good options for me. I'm in need of some original suggestions for places I should be looking.<br>
<br>
Things I DON'T want to hear: <br>
<br>
+Grad school.<br>
+Actuarial Science.<br>
+Vague titles like "Mathematical Analyst." Which industries? What keywords can I search for?<br>
+Programming, unless you have tips on how to bridge the gap between the small projects I did in school and real-world development, or how to get hired with no experience. (Or you can reassuringly convince me that it's really not that hard.)<br>
<br>
It's not necessarily that these are unappealing; I'm already aware of them, just looking for alternatives.<br>
<br>
Is there anything I'm overlooking?tag:ask.metafilter.com,2014:site.265554Tue, 22 Jul 2014 15:28:13 -0800AnonymousMath? College?
http://ask.metafilter.com/265440/Math%2DCollege
The best way to pursue my college goals given my situation. Last summer I went back to college and I took an Algebra and then A Pre-Calc course. I did well enough, A's in both. I never felt like I was really making any connections though. I started a career and as a result stopped pursuing school. I would now like to continue attending school on the side. I want to pursue more math and science courses but am not sure if it is a bad idea to try to take a Calc 1 class given the gap from the previous math courses last year. I am all for learning on my own, and am with several subjects, but math just does not seem like the kind of topic I can jump right into on my own and make any significant headway. Any suggestions on specific resources to get me up to speed or thoughts on what would be best in this case? I never really tried at the math and sciences when I was growing up and only gave it a shot for the first time last summer so I am not drawing on a significant base of knowledge. Thanks, I appreciate it.tag:ask.metafilter.com,2014:site.265440Sun, 20 Jul 2014 17:38:16 -0800mrdrummedCalculus Rabbit?
http://ask.metafilter.com/265439/Calculus%2DRabbit
Is there a game like <a href="http://www.mobygames.com/game/math-rabbit">Math Rabbit</a> out there, but for calculus? Specifically looking for something with lots of game-interface, not Khan Academy.tag:ask.metafilter.com,2014:site.265439Sun, 20 Jul 2014 16:41:00 -0800curious nuwhat percent will result from combining two types of milk?
http://ask.metafilter.com/265223/what%2Dpercent%2Dwill%2Dresult%2Dfrom%2Dcombining%2Dtwo%2Dtypes%2Dof%2Dmilk
If I add 1/100 to 2/100, I get 3/100 or 3%. But if I add one hundred apples, one of which is red, to one hundred apples, two of which are red, I will have 3/200 or 1.5%. I'm very confused now as to what percent milk fat my milk will be if I combine the two types of milk (1% and 2%) together.tag:ask.metafilter.com,2014:site.265223Wed, 16 Jul 2014 09:49:50 -0800windykitesConverting math to code
http://ask.metafilter.com/264616/Converting%2Dmath%2Dto%2Dcode
Wanting to code. Can't read calculus. Kinda stuck. Help? As I spend more and more time coding (just as a hobby, mostly in C and C++,) I keep running into a specific limitation of mine. I'm totally fine with the math, both conceptually and programmatically, but I can't understand much of the research that's in (what looks to me like) calculus. For example, the Wikipedia page that talks about <a href="http://en.wikipedia.org/wiki/Filter_(signal_processing)">signal filters</a> talks about transfer functions, and points to the Wiki page on <a href="http://en.wikipedia.org/wiki/Transfer_function">transfer functions</a>. That page makes no sense to me.<br>
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But, when someone explains something like filters through non-calculus means (for example, <a href="http://christianfloisand.wordpress.com/tag/comb-filter/">this page</a> uses English and flow charts), I can totally follow it and create code based on that explanation.<br>
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Some of the areas that I'm exploring aren't common enough to have English explanations of the calculus. So I'm stuck.<br>
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Is there a way to learn enough calculus to conceptually read it? I don't need to do any math in calculus. I just need to be able to understand what a function expects me to do with it. Basically, how to read a function so that I can implement the idea in code.<br>
<br>
<small>In case it isn't clear, I don't need code samples for filters. I have plenty, and that's not where I typically get stuck. I need resources on deciphering calculus functions.</small>tag:ask.metafilter.com,2014:site.264616Thu, 03 Jul 2014 14:46:12 -0800ericcMath Filter: What is Calculus?
http://ask.metafilter.com/264607/Math%2DFilter%2DWhat%2Dis%2DCalculus
My son would like to know: Is there more to calculus than functions, examples of functions, various formats for presenting functions, and so on? That is, does calculus have unique to it other tools that are not just variations on functions? I dropped out of calculus my first quarter in college at age 18. I am in over my head. Please hope me, serious math geeks.<br>
<br>
Thanks!tag:ask.metafilter.com,2014:site.264607Thu, 03 Jul 2014 12:49:29 -0800Michele in CaliforniaMath book recommendations?
http://ask.metafilter.com/264105/Math%2Dbook%2Drecommendations
Years ago I read John Derbyshire's <em>Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics</em> and loved it. Now I'm studying formal theory/real analysis and I'm finding it really it interesting, but would like to be able to spend my downtime reading about the background of math and also explains some of the concepts. Thanks!tag:ask.metafilter.com,2014:site.264105Tue, 24 Jun 2014 14:09:10 -0800MisantropicPainforestMaximum sum of numbers, one from each set, with constraints
http://ask.metafilter.com/264069/Maximum%2Dsum%2Dof%2Dnumbers%2Done%2Dfrom%2Deach%2Dset%2Dwith%2Dconstraints
Working on a personal project, I am running into a number of math problems of the kind described within. I am not a math expert, so I don't know what to call these kinds of problems, so I don't know how to search for information about them. Here is an example of the kind of problem I am trying to find the answer to.<br>
<br>
There are ten sets of numbers with three numbers each (X, Y, Z).<br>
I want to find the greatest possible sum of (for example) 4 Xs, 2 Ys, and 1 Z<br>
BUT: (for example) If an X is chosen from a set, the Y and Z value from that set cannot be chosen.<br>
<br>
My questions are:<br>
Is there a name for these kinds of problems?<br>
Is there a general method to make sure I always find the greatest possible sum, that will work even when the details change? Sometimes I have more sets, sometimes there are more numbers within each set, sometimes more than one number can be taken from inside a set, each problem is different, but I am always trying to calculate the greatest possible sum.<br>
<br>
If I haven't been clear, please ask questions, and I will do my best to explain.tag:ask.metafilter.com,2014:site.264069Mon, 23 Jun 2014 22:16:30 -0800moonroofHelp Me Learn Math!
http://ask.metafilter.com/263592/Help%2DMe%2DLearn%2DMath
I will be returning to school in the fall to start prerequisite courses for a Physical Therapy program.
I don't know math.
The last time i took math was in high school, and it was basic geometry.
I would like to teach myself primarily, so that i can test into higher classes. The goal is to be able to test into pre-calc, so that i can also qualify for the physics classes as well.
Any suggestions? I don't really care about the method. I was thinking about buying a textbook, but i was unsure of which ones to get.
Thanks.tag:ask.metafilter.com,2014:site.263592Sat, 14 Jun 2014 19:31:10 -0800hiddenknivesHelp Building a Gameplan For a Career In Market Research Analysis
http://ask.metafilter.com/263483/Help%2DBuilding%2Da%2DGameplan%2DFor%2Da%2DCareer%2DIn%2DMarket%2DResearch%2DAnalysis
So, I’ve been doing a lot of thinking about how to land a career in market research analysis. Below are the steps I’ve laid out for myself. Could you tell me if this is a good game plan to get where I want to go? 1. Take a market research class to see if I like it<br>
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2. Get major/minor set up correctly<br>
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3. Figure out LinkedIn and how to network<br>
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4. Follow the advice from the following link https://www.linkedin.com/groups/How-Break-into-Market-Research-1772348.S.84150355<br>
<br>
5. Get an internship in market research<br>
<br>
6. Figure out if a masters is needed and if so how to get it<br>
<br>
7. Get masters<br>
<br>
8. Look for job, using steps 3, 4, 5, and 7 as selling points in my resume.<br>
<br>
9. Get job<br>
<br>
About me:<br>
I’m 25, I’ve never really had a job more serious than a first job kind of job (This summer I’m going to be getting a job at a Dollar General as a sales associate… a job that a 15 year old could do). <br>
<br>
I’ve been in college off and on since 2007 trying to find myself and figure out what the heck I should do with my life. Don’t worry though: I was in community college (and paid as I went) up until Fall 2013, which was my first semester at Texas State University in San Marcos under the major of psychology. <br>
<br>
Combining my entire college career, I have a GPA of 3.10 with 95 earned hours (hours that are unfortunately all over the place). But just in my time at Texas State University under the major of psychology, I have a GPA of 3.88. I don’t know which GPA counts.<br>
<br>
Unfortunately, I have so many random hours that to get a marketing/statistics degree I would have to surpass 120 earned hours, and after you get past 120, you are charged out of state tuition. There is no way I can afford to pay that, so I’m stuck with my major of psychology. My minor right now is in English, which I need to change into something useful. I don’t know whether a minor in statistics or marketing would get me to where I need to be to land a career in market research analysis.<br>
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The reason I’m leaning towards market research analysis is because I am good at math (in that I have never gotten less than an A in a college math class - I’ve taken classes in college algebra, intro to statistics, and just last semester, behavioral statistics). I thoroughly enjoyed my sociology class (got an A in that too) but it was a bit on the easy side, so I don’t know if I’d enjoy it as much if I had a boot camp style professor. I research everything that I buy and cross research it, so I think I may have the right mentality to do research. The reason I chose psychology was to understand people and how they think, which is a big component (just not on an individual scale) in figuring out who will buy what and why. Additionally, I have a knack for writing (my writing may not be the best right now as I’m a little tired).<br>
<br>
Are these good enough reasons?<br>
<br>
A couple of problems/concerns I have about market research analysis.<br>
<br>
I’m a little slow. Obviously, I’ve been fast enough to finish my work and get an A in every math class, but I have to work longer and harder than most people, it seems. But this is how I am with everything… I’m just a slow but steady person. I don’t know if it’s a side effect of my high functioning autism or my perfectionist nature, but it’s just a reality of who I am. I don’t know if this will get in the way too much in my job as I’d be working under tight deadlines.<br>
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Secondly, what if I burn out? I know it’s a hectic career, and I don’t handle stress too well. I enjoy numbers, formulas, and data because they are always predictable and reliable in a world full of crazy chaos, but I don’t know whether or not I could spend the rest of my life hunched over a computer compiling numbers. I may be able to, I don’t know. I know there is more to the job, but this is the heart of it, correct?<br>
<br>
I apologize if that was too long of a question, but I just have a lot to ask and I’m not the best at condensing my thoughts!tag:ask.metafilter.com,2014:site.263483Thu, 12 Jun 2014 18:30:57 -0800ggp88Can you answer this question before my traffic court at 9 am?
http://ask.metafilter.com/263325/Can%2Dyou%2Danswer%2Dthis%2Dquestion%2Dbefore%2Dmy%2Dtraffic%2Dcourt%2Dat%2D9%2Dam
I'm due in traffic court at 9 am. Help me use math to prove I didn't do it. Long story short: officer says I went from 0 mph to 29 mph within a distance of about 200 feet. There is no way I got my little Honda Fit up to that speed within that distance.<br>
<br>
Is there any science: simple math about acceleration; or somehow using the Honda Fit's 0 to 60 speeds (2007 Honda Fit Sport 0-60 mph 8.9 Quarter mile 16.6) to use SCIENCE! to help me be persuasive that I didn't do this.tag:ask.metafilter.com,2014:site.263325Tue, 10 Jun 2014 04:41:06 -0800anastasiav2 problems of combinations and permutations.
http://ask.metafilter.com/263055/2%2Dproblems%2Dof%2Dcombinations%2Dand%2Dpermutations
How many unique ways are there to put X rocks into Y boxes?
(Given two different sets of attributes for both the rocks and the boxes.) Apologies in advance for what is probably some pretty non-standard notation; I am a very amateur mathematician, and I've not studied set theory.<br>
<br>
I'm working on a table of formulas for figuring out various combinations/permutations. The table is missing two formulas, which I've not yet been able to figure out.<br>
<br>
There are a few ways to describe these sorts of problems, but I'm going to use the following metaphor for each of them: How many unique ways are there to put X rocks into Y boxes?<br>
<br>
(In the examples, the rocks are labelled X1, X2, etc., if they are distinct from each other, and simply X if they are not. Likewise for the boxes.)<br>
<br>
.....<br>
<br>
<strong>PROBLEM 1:</strong><br>
How many unique ways are there to put X rocks into Y boxes?<br>
·Every rock is unique. Every rock can be used up to one time.<br>
·The boxes are not unique. Every box can hold an unlimited number of rocks. The minimum number of rocks per box is zero.<br>
<br>
<strong>EXAMPLE 1-1:</strong><br>
If X=2 and Y=2, there are 5 unique combinations:<br>
01. Y() Y()<br>
02. Y(X1) Y() <br>
03. Y(X2) Y()<br>
04. Y(X1) Y(X2)<br>
05. Y(X1,X2) Y()<br>
<br>
<strong>EXAMPLE 1-2:</strong><br>
If X=3 and Y=3, there are 15 unique combinations:<br>
01. Y() Y() Y()<br>
02. Y(X1) Y() Y()<br>
03. Y(X2) Y() Y()<br>
04. Y(X3) Y() Y()<br>
05. Y(X1) Y(X2) Y()<br>
06. Y(X1) Y(X3) Y()<br>
07. Y(X2) Y(X3) Y()<br>
08. Y(X1) Y(X2) Y(X3)<br>
09. Y(X1,X2) Y() Y()<br>
10. Y(X1,X3) Y() Y()<br>
11. Y(X2,X3) Y() Y()<br>
12. Y(X1,X2) Y(X3) Y()<br>
13. Y(X1,X3) Y(X2) Y()<br>
14. Y(X2,X3) Y(X1) Y()<br>
15. Y(X1,X2,X3) Y() Y()<br>
<br>
.....<br>
<br>
<strong>PROBLEM 2:</strong><br>
How many unique ways are there to put X rocks into Y boxes?<br>
·The rocks are not unique. Every rock must be used exactly once.<br>
·The boxes are not unique. Every box can hold an unlimited number of rocks. The minimum number of rocks per box is one.<br>
<br>
<strong>EXAMPLE 2-1:</strong><br>
If X=3 and Y=3, there is 1 possible combination:<br>
01. Y(X) Y(X) Y(X)<br>
<br>
<strong>EXAMPLE 2-2:</strong><br>
If X=8 and &=3, there are 5 possible combinations:<br>
01. Y(XXX) Y(XXX) Y(XX)<br>
02. Y(XXXX) Y(XX) Y(XX)<br>
03. Y(XXXX) Y(XXX) Y(X)<br>
04. Y(XXXXX) Y(XX) Y(X)<br>
05. Y(XXXXXX) Y(X) Y(X)tag:ask.metafilter.com,2014:site.263055Wed, 04 Jun 2014 18:49:18 -0800CustooFintelMortgage shenanigans?
http://ask.metafilter.com/261820/Mortgage%2Dshenanigans
We have an excessive interest rate on our home. We tried to refi, and the appraisal came in a good $40,000 less than it needed to in order to qualify. So some of our more numerically-talented friends ran some numbers for us in an attempt to find alternative solutions and found a weird discrepancy that makes it appear we owe $15,000 more on the loan than we do... My husband bought the house in 2001 before I lived with him. He's always paid the mortgage on time, but the attractive (<em>for investors! not us!</em>) interest rate means it's been resold a kajillion times to multiple mortgage holders. It's currently with (<em>shudder</em>) Ocwen after GMAC failed. <br>
<br>
What steps do we take to determine if something hinky has happened along the way? Do we start by adding up a decade of mortgage payments and saying hmm, that totals <strong>xxx</strong>? Or what? Is there any way of tracking all the companies that have ever held the loan and demanding records?<br>
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(For the purposes of this situation, assume my husband pays everything online and that we don't have paper bills for every mortgage payment made). Thanks in advance, hive mind!tag:ask.metafilter.com,2014:site.261820Tue, 13 May 2014 07:06:18 -0800bitter-girl.comPythagorean Theorem in the original Greek
http://ask.metafilter.com/261768/Pythagorean%2DTheorem%2Din%2Dthe%2Doriginal%2DGreek
I'm looking for a textual version of <em>a</em><sup>2</sup> + <em>b</em><sup>2</sup> = <em>c</em><sup>2</sup> that is as old as possible, among all the Greek sources. I am looking for the earliest statement of the Pythagorean theorem in Greek. I want it to be as text, hopefully something like "the sum of the squares on the sides is equal to the square on the hypotenuse". <br>
<br>
- It's probably not stated that way, but that's fine.<br>
- Greek text is a requirement.<br>
- Older is better.<br>
<br>
I've gotten some indication that I should look in Euclid's <em>Elements</em>, but haven't managed to track that down. I thought there might be some MeFi classicists who had this at their fingertips. Thanks.tag:ask.metafilter.com,2014:site.261768Mon, 12 May 2014 10:57:31 -0800benito.straussHow do I calculate combined percentages?
http://ask.metafilter.com/261686/How%2Ddo%2DI%2Dcalculate%2Dcombined%2Dpercentages
Mathfail: I'm considering supplementing my cat's food with plain meat. I'd like a rough idea of how much it would bump percentage of calories from protein and fat. Here are the numbers I'm working from:<br>
<br>
Total calories: 215<br>
<br>
Canned food calories: 180<br>
% calories from protein: 32%<br>
% calories from fat: 59%<br>
<br>
Meat calories: 35<br>
% calories from protein: 77%<br>
% calories from fat: 8.5%<br>
<br>
If I combine these together, what are the combined calories from fat and protein?<br>
<br>
I'm looking at a couple of canned foods, and would be grateful if you could walk me through the calculation. I feel dumb asking this - I'm sure I learned how to do this at some point in my life, but my math skills are rusty.<br>
<br>
(For the curious: this is to compare numbers of cheaper food + meat to more expensive food.)tag:ask.metafilter.com,2014:site.261686Sat, 10 May 2014 13:40:14 -0800moiraShould my math student have some Unix skills?
http://ask.metafilter.com/261436/Should%2Dmy%2Dmath%2Dstudent%2Dhave%2Dsome%2DUnix%2Dskills
I think my son, who is on an AP math trajectory in high school, would benefit from getting some familiarity and basic programming skills in the Unix world. I've noticed math depts in some universities include study of these skills in early years. Are there some tutorials we could use in the OS X environment to get a leg up? He is competent with computers but has no programming or command line experience.tag:ask.metafilter.com,2014:site.261436Mon, 05 May 2014 21:02:47 -0800Mei's lost sandalWhat Major and Career Should I Look At If I Enjoy Math?
http://ask.metafilter.com/261370/What%2DMajor%2Dand%2DCareer%2DShould%2DI%2DLook%2DAt%2DIf%2DI%2DEnjoy%2DMath
In studying for my Behavioral Statistics final (it’s a statistics class dealing with psychology research methods) I’ve realized something. I actually kind of enjoy math. As long as I don’t have to memorize formulas (as long as they are right there as I’m going through the work) it’s actually kind of comforting and fun. In fact, every math class I’ve taken in college (I’ve taken two remedial algebras, college algebra, and regular statistics before this class) I’ve enjoyed and made an A in.
I’m really struggling about what I want to major in (I’m in psychology but I don’t have it in the gas tank to get a PhD), but I know that a lot of people don’t like math. They don’t get it. I do, so I’ve got something there, right?
The only problem is, I don’t know what to do with it. These are the parameters… maybe you can think of something that fits? -I’ve been in college since 2007 floundering around in terms of what I want as a major. At the VERY MOST, I am willing to get a masters, but I’d rather just get a bachelors.<br>
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-I want to make around 60-70k a year at the least.<br>
<br>
-I like people, and the idea of working in teams, but sometimes I suffer from social anxiety. I don’t want some high-pressure sales job.<br>
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-I like math because of its formulaic, step-by-step, one-thing-leads-to-another nature. It’s predictability in a world of chaos. I’m not a big fan of unpredictability and that’s why it’s comforting.<br>
<br>
-I like discovering new things, but I’m not a trailblazer… I work as a follower, a team member.<br>
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-I’d rather not be behind a cubicle working on mundane paperwork. I want to do something that has meaning and excites me.<br>
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-I want to have time for my other hobbies such as family, friends, and being outside. <br>
<br>
-It would be very nice if the job were in demand and not some extremely highly competitive field. I value security very very much, and the idea of graduating college and being lost again is terrifying.<br>
<br>
-I know that every job can be stressful and unfun at times, but I’d prefer this job to be on the low-stress end of the spectrum. I don’t deal very well with stress.<br>
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I may be just being too picky here, and perhaps such a job that fits all of those requirements does not exist. But maybe there are careers out there that fit pretty well, if not perfectly.<br>
<br>
The most important aspects are the salary, not getting the PhD, and a non dog-eat-dog gladiator ring of a competitive field. And I’d rather it be fun and engaging, not boring and soul-draining.<br>
<br>
Does anyone have any ideas?tag:ask.metafilter.com,2014:site.261370Sun, 04 May 2014 17:18:24 -0800ggp88Size of earth to solar system vs drop of water to Mt Everest?
http://ask.metafilter.com/260903/Size%2Dof%2Dearth%2Dto%2Dsolar%2Dsystem%2Dvs%2Ddrop%2Dof%2Dwater%2Dto%2DMt%2DEverest
Can someone please tell me (if you could show calculations, that would be wonderful) what the ratio of ratios would be for these two numbers: a) the volume of the earth compared to that of the solar system and b) the volume of a drop of water compared to that of Mount Everest?tag:ask.metafilter.com,2014:site.260903Fri, 25 Apr 2014 12:35:24 -0800shivohumWhy is the center of a circle often given as (h, k)?
http://ask.metafilter.com/260472/Why%2Dis%2Dthe%2Dcenter%2Dof%2Da%2Dcircle%2Doften%2Dgiven%2Das%2Dh%2Dk
Why are the letters 'h' and 'k' often used to represent the center of a circle in the standard equation of a circle:
(x - h)<sup>2</sup> + (y - k)<sup>2</sup> = r<sup>2</sup>
are 'h' and 'k' short for something? I might guess 'h' is short for 'horizontal', but I can't imagine what 'k' is for. So why do we use (h, k) rather than (a, b) or some other pair of letters? My Googleing shows I'm not the first person to wonder this, but no one seems to have received a good answer.tag:ask.metafilter.com,2014:site.260472Thu, 17 Apr 2014 10:21:23 -0800Reverend JohnWhat's a good topic for a one-hour math lecture?
http://ask.metafilter.com/260101/Whats%2Da%2Dgood%2Dtopic%2Dfor%2Da%2Done%2Dhour%2Dmath%2Dlecture
I work as a math tutor at a community college and have the opportunity to spend an hour teaching math to a group of students preparing for a the college's math placement test. Now, I don't know what's on the placement test, but I want to teach something that's more engaging and conceptually accessible than "here's how to multiply (4x+3)(2x+5)", since I can't possibly review all of high-school math in an hour and don't think the students will get much from just another lecture. What are some interesting topics that I can explore that will be accessible and memorable?tag:ask.metafilter.com,2014:site.260101Thu, 10 Apr 2014 10:24:33 -0800LSKArticle about Common Core math
http://ask.metafilter.com/259860/Article%2Dabout%2DCommon%2DCore%2Dmath
Trying to find an article I read sometime in the last three months about Common Core math. The article started out talking about why Common Core math does make sense. It then described how basic addition and subtraction seem simple but are actually quite difficult concepts at a young age, in addition to being boring. In contrast, the basic concepts of knot theory and set theory are more interesting and more accessible at a young age. The researcher in the article (possibly the author) wanted to find more concepts that are interesting and accessible - I think there was a phrase about finding "advanced but conceptually simple" topics - to make math more appealing intuitive for kids. <br>
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I think I read this in the New York Times, but I'm not sure.tag:ask.metafilter.com,2014:site.259860Sat, 05 Apr 2014 19:56:31 -0800Questolicious[MathFilter] Taking for-credit math classes online
http://ask.metafilter.com/259817/MathFilter%2DTaking%2Dfor%2Dcredit%2Dmath%2Dclasses%2Donline
For professional and academic reasons, I need to take a number of college-level math classes (mainly Calculus and Linear Algebra) in a relatively short period of time (4-6 months). They need to be online, for-credit, and I need to be able to do them at my own pace, meaning faster than a normal 1-course-per-semester flow. I've already found <a href="https://netmath.illinois.edu/">https://netmath.illinois.edu/</a>, but the classes are terribly expensive, so I'd like to learn of other alternatives that don't cost as much.tag:ask.metafilter.com,2014:site.259817Fri, 04 Apr 2014 18:35:53 -0800dcrochaVon Neumann I am not
http://ask.metafilter.com/259473/Von%2DNeumann%2DI%2Dam%2Dnot
I’ve spent my 20s building a BS “identity” as an “analytical type of person". Help me grow up. Snowflakes inside. I should be graduating in the next few months with an economics PhD. When I finished high school I didn’t go to university directly. I worked and during that time decided I wanted to study it at undergraduate level. (Understanding things about the world which seemed powerful and mysterious was originally the attraction). Economics has lot of math. Previously I had been very poor at math. I’m in a European country where one can choose to not study math in last two years of high-school, and I didn’t. I enrolled in one of the few university courses in my country which at the time accepted economics students without having studied math for the last two years of high-school. As an undergraduate at university I studied relentlessly (and also brought my math up to speed –in fact further than what was necessary as I wanted to do graduate level econ study - in my spare time calculus, linear algebra, statistics, probability, a little bit real analysis) and did very well as far as that course went. <br>
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Then I did an MSc in econometrics (no GRE or entrance tests there). During that year I got a chronic fatigue illness and struggled to complete my MSc thesis. Then I applied to a grad school which enabled me to again avoid GREs and entrance tests. <br>
Grad school was a disaster. I hated the grad school courses. I realised I also have a problem following presentations and that I am slow at reading papers. Imposter syndrome set in. My chronic fatigue continued (I should have taken time off but didn’t). I found that I had been focussing on analytical deduction at the expense of evidence, (and I was weak in dealing with latter.) I also found the various expected standards inconsistent and therefore confusing. When I look back, the only things I enjoyed in four years were writing scripts in statistical software packages for data collection, processing and analysis (the problem was self contained, the only criterion for success was “does it work?”, there was no-one to compare my performance too). I almost quit, but finally submitted, and passed. I dislike my thesis, don’t trust the results and do not want to publish them, despite the reassurances of my supervisors. I don’t think that I have a future in academia.<br>
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All the while I’ve been aware that although I’ve learned a lot of math compared to what I used to know, I’m still not any good with numbers. Probably a little less hopeless than before. But it takes me ages to work out anything in my head, and I just can’t do it under pressure. I just failed to get through a basic math test for a government job, which involved no above high-school math at all. I realised that all I can do is (not advanced) “math with letters” and next to no “number sense”. I’m also aware that my understanding of how the economy really works, despite all this study, is probably worse than someone who didn’t do any of it. <br>
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But more importantly, I’m pretty sure that I have spent most of my 20s trying to create an idea of myself of some “analytical type person” which I never was (and attempting to avoid disturbing but potentially useful evidence to the contrary). I believe that I’m an anxious and insecure person and somehow I think it served as a shortcut to an adult identity. But now I’m aware that it’s nonsense (and actually harmful to becoming a mature adult), but at the same time not able to detach myself from the most unhelpful thoughts – sometimes feeling stupid and worthless, and more generally having a fragile ego. <br>
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How can I move forward? I’d like advice on detaching my sense of self-worth from this “analytical type of person” idea that I’ve built up over the years. Very soon I'm going to need a job, and I’d like to find a job in which I feel good enough. Have any of you stuck with a field or some broadly defined area, despite a feeling of large intellectual limitation, dealt with those feelings and made it work?tag:ask.metafilter.com,2014:site.259473Sat, 29 Mar 2014 18:24:35 -0800AnonymousCalculus after being away from algebra for some time. Help me.
http://ask.metafilter.com/259184/Calculus%2Dafter%2Dbeing%2Daway%2Dfrom%2Dalgebra%2Dfor%2Dsome%2Dtime%2DHelp%2Dme
I am going to grad school in the fall. Hooray! Problem: I have to take calculus before I start and I am kind of freaking out. Everything is great about the grad program I've decided to attend. The only problem is that I found out with my admission that they want me to have calculus before I start. I haven't had calculus. It was news to me that I needed to do it before starting (non-math intensive field), but attending a different program that doesn't require it is not really a good option at this point, as this program is far and away the best financial option I have.<br>
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They said I can take any sort of calculus I want and that it can be at a university, community college, or online. I have opted to take a course called "Calculus for Business, Management, Social and Life Science" at my local community college. It starts in one week. <br>
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I had trig and pre-calc in high school, but other than that I have been away from higher level algebra for kind of a long time. I took stats recently with no problems and I also took Trig-Based General Physics last fall without too many problems. I also took the GRE last summer which required me to basically re-learn high school level algebra and geometry and did well. <br>
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I am more or less good at math, but I am really, really worried about my algebra not being up to snuff and failing miserably. I feel more or less comfortable working with basic trig, quadratic equations, basic algebraic operations. I have to go/no-go to all my grad programs by April 15th, so I'm concerned that I will accept the offer, turn down the others, and then fail calculus and totally screw myself.<br>
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I spoke with the professor about my situation. He scared me with how difficult this was going to be. He also said there are some others in the class in a similar situation to mine. I also have people close to me who are engineers/math students who I can enlist to help me a bit. I don't need to excel in the course, but I do need to pass.<br>
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-How screwed am I?<br>
-Are there any strategies that can help me best succeed in this situation? Resources? Things I'm not thinking of?<br>
-I am willing to dedicate as much time as it takes really to make this work. What should I be preparing for/reviewing?<br>
-Any other advice?<br>
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Thanks everyone.tag:ask.metafilter.com,2014:site.259184Mon, 24 Mar 2014 11:51:35 -0800The Pantless Wonder