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917 posts tagged with math.

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## Why do we have order of operations in arithmetic?

Why do we have order of operations rules in arithmetic instead of just strictly evaluating expressions from left to right (possibly with parenthesis for grouping if we really wanted to change the order)?

## Is this science or a sort of engineering? How do I learn more about it?

My ignorance of science and engineering concepts, procedures, and methods of calculation is holding me back from tackling a whole mess of fun stuff. But what fields am I even interested in, and how can I learn more? Where do I begin? [more inside]

## Well-written math

Which mathematicians write exceptionally well or exceptionally clearly? (Individual books or articles would also be acceptable.) [more inside]

## Where can I take an online linear algebra course this summer?

I have $800 for tuition reimbursement, and would like to take a linear algebra online course this summer. It doesn't matter if its for credit or not. Thanks!

## Regarding the M in STEM

What are some of the newest methods being used these days to teach young children arithmetic? [more inside]

## Was Fifth Grade math always this hard?

Can you show us how to solve a math word problem? [more inside]

## Singapore Math

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]

## You Can't Handle the Proof!

Working through Apostol's Calculus Volume I for personal development. Stuck on a proof. Can you help? [more inside]

## Table top brainteaser puzzles

## Why can't I differentiate this nomal/Guassian distrubution?

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?## What to include in a training on maths for business people?

I've been asked at work to come up with a list of topics that could be included in a training course around basic maths for business people, and I am finding it hard to find suggestions for topics. [more inside]

## The Gambler's Fallacy, of course. But maybe...

A coin flips three times and comes up heads 2/3. Not suspect.
But a coin flips 100,000 times and comes up heads 2 out of 3 times, that starts to look fishy. The standard probability of this is always roughly 50-50, but assuming a 2/3 ratio pointing to a "rigged" coin, how could you plot the increasing likelihood that a given coin is rigged? [more inside]

## Percentage Question

Help me understand percentages. [more inside]

## Bad at math

I have a question about probability math. I am essentially flipping a coin (except instead of a 50/50 chance, my odds are 50.5% heads, 49.5% tails).
I am concerned with the probability of me hitting heads (a 50.5% chance) several times in a row. [more inside]

## What is the slowest-growing whole number sequence?

What is the slowest-growing non-repeating, non-trivial* whole number sequence? [more inside]

## I need to be able to memorize several formulas for a test next week

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.

## Good Idea or Recipe For Hell?

I am going into my last semester of college, and I have signed up to take Calculus III, three years after taking Calc II. This may be a great idea or a terrible one. [more inside]

## Narrowing my son's grad school search

My son is a junior physics/math major at a small midwestern state university. He needs to start looking at graduate programs. He would prefer to stay in research or academia. How can I help him start this process? (B.S. for me) Location is not an issue. It's more a question of what programs offer the best opportunities and fields of study. How can we find out that kind of information? How can I help him start with a reasonable number of candidates?

## Looking for a basic review of math (algebra, geometry, fractions, etc)

I have to take a math placement test in the next two weeks that will determine which college class I will place into next semester (January). I have already taken Math 1010 (Intermediate Algebra) and 1030 (Quantitative Reasoning) long ago but those credits do not count any longer towards this current placement. I need to test to see where I fall now. I'm hoping to get into Math 1050 (College Algebra) ideally. My skills are rusty though. [more inside]

## Becoming Fluent in Predictive Analytics

I work in a University managing the broad based direct mail, email and calling programs. I have zero undergrad or graduate experience with math, business or the social sciences. (Aka, I can write a really nice essay...) I would like to chart a path to being recognized as an expert in predictive analytics. [more inside]

## Career advice for math major (also competent programmer)?

I like math. Programming is OK, but I don't want to make it my thing. What careers should I be looking at? (Special snowflake details inside.) [more inside]

## Educational mathamatics apps for adults that will work on an iPhone?

I am looking for adult-oriented iOS apps that will help improve my math skills. [more inside]

## extrapolating temp/energy use difference from small boxes to my condo

Physics geeks! Help me save energy! How do I estimate how much less energy will be used by light siding vs gray siding, based on an experiment with small boxes? I made some identical boxes, put them in the sun, measured temperatures, and am trying to figure out how to scale up. The net has info about different roof colors, but not siding colors. [more inside]

## Teaching in France ??

Hi, my last questions have been about learning French, then skiing in France (thank you for all those answers to those questions)...and now I'm thinking "what about working in France"? [more inside]

## Am I actually an Aspie?

I'm a 45 year-old adult who has just been diagnosed with Asperger's Syndrome. At least, my counselor and my ex- both believe I have it. I don't believe I can be an Aspie because I am *phenomenally bad* with *both* computers *and* math (details on request). Are there Aspies like me?

## Probability and a rather unique deck of cards.

Each card in a certain deck has three letters on it.
The first letter is either A, B, or C.
The second letter is either D, E, F, or G.
The third letter is either H, I, J, K, or L.
Every possible combination is represented exactly once in the deck. Ergo, there are 3x4x5=60 cards in the deck.
How can I determine the probability that a hand of X cards, drawn randomly from the deck, will include at least one of each of the letters?

## Math for CSI

My girlfriend is applying for to work for the city as a crime lab trainee, a position they will train her for, but will be tested for basic knowledge (they are looking for someone with a two-year degree, apparently in anything). The test will include math. What do you think she will need to be sure she's solid on? [more inside]

## Studying the masters, not their pupils (budget edition)

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]

## How do you help people have an epiphany about difficult concepts?

How do you describe the basic concepts of a difficult subject you know a lot about that makes it "click" for a beginner? [more inside]

## Math game that featured Bach and Mozart

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 want to show a movie clip in a public talk. Is this legal?

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!

## Modern Zoombinis?

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.

## Tools For the Spatially Challenged: Couch-Movers Edition

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 Puzzles, Please!

"Math for Smarty Pants" was awesome -- recommend me more books like that for a kid who loves math puzzles. [more inside]

## I want to be able to read CS and math research papers with ease.

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's~~Wolfram MathWorld, and still not feeling like I retained everything. [more inside]

## Rearranging the formula for Compound Annual Growth Rate

How do you rejig the formula for CAGR to get the starting value when you know the other variables? [more inside]

## Longitude lines in perspective, what shape are they?

I'm drawing/painting a globe (in time lapse, so the sun appears to rise) and trying to figure out what shape, exactly, the longitude (not latitude) lines are when a globe is flattened into a circle (I know I can just trace them, but I've gotten curious). So, the outermost longitude lines are tangent to the circle, they are half-circles, and the centermost line is a straight line from pole to pole, it's the progressively flatter curves in between that I'm trying to figure out. Do they have a name? Are they catenaries? Are they the curves of progressively larger circles? How do I construct them (easily)? Example image: HERE

## Not my high school TI-82.

I'm taking Calc I this fall. I can borrow a graphing calculator for actual exams, but don't want to actually purchase one for day-to-day--or haul it around with me. I have an iPhone and a Nexus 7. Is there a graphing calculator app in one or the other app store that is clearly superior? I'm willing to pay, but under $10, ideally.

## Where can I find sample arithmetic problems like this one!

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]## I was banned from collegeconfidential just for asking for some help?

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]

## Best option for completing two college math courses

What is the best option for a working professional to complete two undergraduate level math courses - linear algebra and differential equations - in order to bolster my graduate school application? [more inside]

## Textbook Cross-reference for different editions

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]

## Help me convert this graph into a table.

I have a bitmap of a chart (in polar coordinates) that I would like to convert into a format that some plotting package can recognize, and then retrieve values from the chart at specific intervals. How do I do this? [more inside]

## Anyone good at math, semi-circles and areas PLEASE HELP!!!!

So I am trying to figure out how to charge for a product that is a semi-circle. I charge per square feet.
The client ordered a product that was 25 feet in diameter and 6 feet deep (radius if it were a full circle), then changed it to 20 feet in diameter and 10 feet deep (radius if it were a full circle.
I tried to figure out the area of the space as half of 3.14 x radius squared. But there is no part of the equation accounting for the change in diameter... a little confused since this is the first time we are doing a semi circle.
I feel like the it shouldn't work out to the same price. If I were charging $1 per square foot, what would the difference in price be?

## iPad math apps for a 10-year-old?

My son is 10 years old and going into 5th grade in the fall (but he usually does 6th grade math). He likes Stack the States, and we're looking for a math app with similar appeal. We already have Sushi Monster and his younger sister loves it, but I'd like something more challenging for him.

## Find standard deviation in Excel, but first develop a labor-saving trick

Help me with statistics and Excel. Especially help me if you know any labor saving methods. I want the median, mean and standard deviation for the average price of all items sold, but my spreadsheet-full-of-data doesn't tell me the price of each sale -- just the average price per store, and the number sold at that store. Something like this: [more inside]

## Help me understand fractions

## Returning to grad school after 2 year hiatus

So I'm beginning a statistics PhD program this fall and I'm concerned that my math skills have gotten rusty since I haven't done anything related for the past two years. I've been working as an actuary since I graduated college but I don't do that much math--mostly a lot of programming. Has anybody been in a similar situation to me? How was the adjustment for you? I'm considering retaking advanced calculus and linear algebra during my first year (probably next summer before I take 2nd year advanced courses) just to refresh myself again. I'm aware some people may think this is kind of pathetic but I'd rather be safe than sorry. Besides, it's only my first year. Is this frowned upon? [more inside]

## Scale my function for a line graph

Math-filter: I have a line chart in Google Docs that plots three columns of data over time. Data in the first two columns ranges from 0-1000, but data in the third column ranges from 3-9. I'd like to "scale" Line 3 (maybe this is the wrong word?) to be able to compare its value over the same graph space as Lines 1 and 2. [more inside]

## Educate me on modern mathematics!

My math knowledge ends just past Newton. What books provide a good, relatively general-audience introduction to the past 150-250 years of problems and developments in mathematics? [more inside]