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. [more inside]
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?
You want to walk 10 blocks north and 10 blocks east. It would be shorter to walk along the hypotenuse, but the same distance to walk 1 block north, then 1 block east, then 1 block north, etc. it seems that if the blocks were infinitesimally short, it would approximate the hypotenuse, but alas, walking 10 blocks in one direction and then 10 blocks in the perpendicular direction is the same as dividing it up. What gives?
I have an Excel spreadsheet I use to track glucose readings. There’s a value diabetics use called “A1C” which looks at the last three months of readings. It's based on a blood test, but can be estimated by averaging your readings for the last three months. I try to track every day, but I can’t reliably say “look at the last 90 values” – so I’m wondering how to set up a formula to tell it to only look at readings going back 90 days, not necessarily 90 readings. More inside. [more inside]
This will be easy for someone, but math is my second language so I'm at a loss. How do I solve for the percentage of a TOTAL budget, when one line item is unknown (and is part of the total budget)? [more inside]
Please help with this probability related math problem. [more inside]
I am part of a group working on a policy document for the mitigation of traffic issues (e.g. speeding). Stakeholders are having a hard time with a particular criteria which reads as follows: "85th percentile speed is in excess of the signed speed limit by 5 mph or more." [more inside]
I'm trying to buy a copy of a famous Russian geometry textbook, Kiselev's Geometry (link to a recent English translation), in the original Russian. Any copy of any edition will do; in fact, a used copy would be mildly preferred. However, I speak no Russian whatsoever, so I'm having difficulty figuring out how to go about this, partly because I don't even know what to search for on a Russian-language site! How can I complete my task? [more inside]
I'm running a fantasy football league in which we have 10 teams. The first 9 weeks were round-robin style, with each team playing each other team exactly once. My plan was to schedule weeks 10 through 13 (four weeks) such that each team played a mix of stronger and weaker opponents based on the standings in weeks 1 through 9, then use the week 1-13 results to seed teams for the playoffs in weeks 14-16, but I'm having trouble developing an approach for generating these balanced week 10-13 matchups fairly. Any ideas? [more inside]
I have a set of data: D(t). 5000 samples. Scatter-graphing makes some patterns clear (D-mean increases with t, for instance). D and t are always positive. I want to characterize these, statistically. [more inside]
For my son’s high school history class, he has been assigned an in-class argument/opinion essay. The teacher ended most of the lecturing this week and has given them time to prepare thesis statements for the essays. Here is where it starts to get complicated (at least to my son and me): [more inside]
In one of these puzzle games like 2048 or Threes, where you merge tiles to create higher numbers, is there any way to prove what is the highest possible tile number that can be created given the rules and dimensions? [more inside]
I have just completed my MSc in mathematics in Europe. I do enjoy math, but I spent my uni years feeling like a autodidact hippie marooned on an island full of Mr and Mrs I-Want-A-Good-Job. My main interests revolve around humanities (literature/history/anthropology) and economics (but not finance), and instead of starting a "stable" well-paying career I dream about something inter-disciplinary. I am very open to earning little money and relocating just to do kind of work that engages those skills. What are some random uses of my degree? [more inside]
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.
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? [more inside]
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. [more inside]
I'm looking for a textual version of a2 + b2 = c2 that is as old as possible, among all the Greek sources. [more inside]
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. [more inside]
Working through Apostol's Calculus Volume I for personal development. Stuck on a proof, again. Can you help? [more inside]
What is the best way to take grad level notes that feature tons of text, math equations and diagrams, during class, while reading books, and while reading research? Ability to search and organize a huge plus! Digital or non-digital solutions considered. [more inside]
Okay, I'm in NYC and I need a PI related T-Shirt for Pi-Daytomorrow... Anyone know of any stores where I can get one? (It's too late for an online order)
I'm trying to help my 3rd grader with his math homework, but we are stuck on one problem. I can solve it using Algebra, but I'm trying to figure out how to explain it to him using the Singapore method that he's taught in school. Note that he hasn't learned how to add negative numbers, which puts a crimp on the methodology. [more inside]
Working through Apostol's Calculus Volume I for personal development. Stuck on a proof. Can you help? [more inside]
Have a look here. I'm assured that differentiating 1, with respect to x, gets you 2. Now 2 is - I think, and correct me if I'm wrong - equivalent to 3. The problem is I can't see how 3 is the result of differentiating 1. What's more, an online solver produces something (that looks) very different. Can someone help me out?
Help me understand percentages. [more inside]
I'm taking a numerical methods class and there are all these discretization schemes of partial differential equations named after pairs of dudes and they all are kinda the same, maybe a bit different in indexes.... I'm trying to organize it all in my head, like a frat house, with the dudes that worked on the same scheme being roommates, but it seems to be taking a long time to actually "find" a place for each scheme in their "rooms" and keeping it there in a sort of visual arrangement. Test is no books no notes, and everything kinda of just jumbles inside my head right now.
I am a frequent buyer of <$5 books on Amazon. Lately I am interested in math treatises but have been unable to find any that aren't way out of my price range. Am I being way too demanding? [more inside]
Around 1995 I played a game on the Mac in school that was for educational purposes, supposedly for the purposes of drilling math skills, and had Mozart Symphony no. 40 (1st movement and but I think 3rd as well), Bach BWV 999, and possibly some Paganini as well, as background music. Do you know what it was?
I'm giving a public talk about Goldbach's Conjecture. There is a crazy Spanish movie in which a character is famous for having proved the conjecture. Can I show a clip or two from this movie in my public talk? The talk will be in a bar, and there's a $5 suggested donation, so I don't know if that counts as charging people (if that affects the legality of my idea). Thanks!
What is the modern equivalent of 1995's lovely LOGICAL JOURNEY OF THE ZOOMBINIS computer games? They taught math logic skills rather neatly for children, but I don't have a computer that will run the old games.
Wizards of Hive, Before I buy that 90" couch from a friend, how can I make sure I'll be able to get it up my L-shaped stairs? Sure, there are a lot of variables. But is there a tool or methodology for figuring this out ahead of time (presuming I know the depth and height of the couch too)? I don't think I have the cardboard to build a mockup. This couch is 50 miles away and can't be returned. Thanks!
"Math for Smarty Pants" was awesome -- recommend me more books like that for a kid who loves math puzzles. [more inside]
I often find myself crossing interdisciplinary lines and reading research papers, trying to understand some new practice or algorithm in math or computer science. I start out thinking "I just need to understand these basic concepts and I'll crack this", but end up with a very tired brain at 5am, having tried to mainline dense trees of Wikipedia and
Eric Weisstein'sWolfram MathWorld, and still not feeling like I retained everything. [more inside]
How do you rejig the formula for CAGR to get the starting value when you know the other variables? [more inside]
I'm taking a standardized test on Wednesday with the Government of Canada and they ask individuals four types of questions. The type that I struggle with are the arithmetic problems... specifically determining the formulas to solve word problems. I was hoping someone might be able to point me in the direction of a website or easily accessible textbook to practice today and tomorrow before the test. [more inside]
Summer vacations are coming up and I am going to use some of my free time to learn physics and math, subjects that I love. In order to do that i asked collegeconfidential.com if anyone had "exclusive study materials" from their university which they could share. I mentioned that I would like to have acess to tests and exams from other universities and I could give some good materials collected by my colleagues of the physics and math course in exchange. [more inside]
Is there some place I can find cross-reference guides to match up material and problem sets between different editions of the same textbook (specifically math textbooks) ? [more inside]
I tutor a boy who is moving from 4th-5th grade. He's at grade level in most subjects, above grade level in reading, but getting an Elvis Presley head in math. Can you help me find ways to help him be less intimidated by math, allowing us more time to learn and practice before his eventual mental shutdown each session? [more inside]
I have a song at 150 bpm, perfectly in tune. I want to repitch it down to around 120 by slowing it down. At which bpms will the notes be at pitch?
Please help me pronounce this formula related to projectile motion as it would be spoken out loud: L = v0^2 sin2θ / g [more inside]
[mathfilter] please give me some example algebraic structures that are not commutative, with exotic identity values. [more inside]
Dear Mefites, a long time ago I got a degree in graphic design but never worked in the industry. Along the way I somehow (don't remember how or why or when) became interested in math and I finished a graduate diploma in maths as a distance learning course in my free time. I am considering applying for masters programmes in maths or related subjects but ... can I? Should I? [more inside]
What is the math (physics?) going on in this very cool-looking, equations-as-art necklace?
Which employers still use a basic math test as part of the application process? [more inside]
Can a transcendental number such as pi, be raised to an irrational, but algebraic power resulting in an algebraic solution? Complex solutions would be acceptable. There might be a quick proof here, or there might not be. - Thanks for any help you can offer answering this! (And I promise that this isn't for a class or anything like that!)
Writing a script, need a few believable, throwaway lines for a character. A guy running a TGI.Friday's-like bar praises his bartender, a math genius, for giving him an idea that saves money and improves the business overall. An example of outside-of-the-box thinking that enforces that our math-genius-in-disguise really is a genius. Bonus points if the idea skirts the line of legality -- something funky with accounting, maybe? [more inside]
Can you recommend short, easy-to-understand math writing I can read before bed? [more inside]
I'm wondering, after breakfast, and a shower, and a commute, and coffee - what is next? [more inside]
I have roughly 20 people who each need a project. I have 27 projects and don't want anyone to share a project. I let the people pick their top five projects and rank them so I know who wants what. What is the best (easiest...) way for me to fairly figure out who should get what project so that the most people get their top choice, or at least one of their top choices? [more inside]
If I want to draw something in one-point perspective, say, like a set of railroad tracks where the vanishing point is on the horizon, and the tracks are represented on the picture plane by an equilateral triangle (they appear that way to the viewer), the apex of the triangle being the vanishing point on the horizon and the base of the triangle is where the tracks meet the picture plane, how do I calculate where the railroad ties would be? (Given that in 3D they are evenly spaced. Also, I'm not really concerned with the thickness of the ties -- we can consider the ties to simply be horizontal lines.) [more inside]