Mathematics

I found this article very interesting and thought you math guys would really enjoy it. It relates to the probability of two people out of 40 having the same birthday in a room of people who's birthdays are sequential. Surprisingly enough, it's not 11%, but in fact it's 90%. http://www.damninteresting.com/?p=402#more-402 That'll probably explain it better than I can.

I am interested in knowing how to find the distance along a function between two values. I am surprised to see that this kind of problem is never encountered in the highest level mathematics in high schools in Australia and decided to research it myself. I would appreciate a term that might be useful to google or perhaps a link to a wiki article or something. Thankyou, BigMoosie

2 + 1 + 3 + 2 = 8 The number 21328 has a unique feature: The sum of the first four digits equals the units digit. How many EVEN five-digit numbers have this unique property?

i'm trying to prove that a funtion f(being f injective, and it's inverse are symmetric to the line y=x i can prove that the any segment defined by the points (fx,x) (x,fx) is perpendicular to that line, which also contains the midpoint of the segment. SO the line is the perpendicular bisector to any segment (fx,x)(x,fx) however i realy don't know where to go next? is this enough?whats is the definition of symmetry axe?

Im sure they has been a thread on this but I want to know if anyone knows how to solve a rubik's....except with a more beginner solution.

Hey guys, This is just a grade 10 level math question that I have, that will be extremely simple for you, but I am unable to understand what to do (I am in Grade 10 too). The problem is that there are 9 people playing sports, and they need to divide up into teams of 2. How many different ways can they form their groups? The answer for this question is 20, but how do you get that answer? I am totally confused, and all your help in clarifying this matter is greatly appreciated. Thanks, RedAlert

Hello, I was wondering if anyone can give me some information... I was wondering how many 3-digit Prime numbers there are, and what they are and which 4-digit numbers are also Prime. There was something I was trying to work out about them involving orders of magnitude between different Prime numbers, but I don't know where to look for that kind of information. Thanks a lot for any help you can offer!

There is a large square of a side s containing a small circle with a radius r, a point is chosen randomly within the square, what is the probability of the point being within the circle? I'm tempted to think that the awnser is [math]\frac{\pi r^2}{s^2}[/math] but the following question is: Show that if r increases by 20% then the probability increases by 40% If [math]r_{1}=1[/math] and [math]r_{2}=1.2[/math] then [math]\pi r^{2}[/math] increases by 44%. Where have I slipped up?

Tried to format this as best as possible, a machine given an input of x, outputs the following, where x is 116 What is the relationship between the given input and output per number of positions? Elements Positions E Pos1 Pos2 Pos3 Pos4 Pos5 Pos6 Pos7 Pos8 x = 69 216 x, x= 69 172 16 x,x,x= 69 172 100 122 x,x,x,x= 69 172 100 14 74 x,x,x,x,x= 69 172 100 14 62 26 x,x,x,x,x,x= 69 172 100 14 62 110 40 x,x,x,x,x,x,x= 69 172 100 14 62 110 92 58

Ok, I remember learning about partial fraction decomposition a while ago, and how it involved separating a fraction into the 2 fractions that existed before they were multiplied by a fraction of 1 to obtain identical denominators. However, I have forgotten how to do this, and I was wondering if someone could refresh my memory on how it's done. Thanks, john

This is probably a stupid question, but I was wondering if a point is 0 dimensions, and a line with no width is 1 dimension, can you generate 1 dimension from 2 points of 0 dimensions ?

could you please help me with this question I would be very much obliged. I cant hack it for my exam A racing car of mass m travels along a straight road. While travelling the racing car is subject to a constant frictional resistance equal to ma (a is a positive constant) and aire resistance equal to k times thee square of its velocity v. The engine of the care can rpovide a constant propelling froce equal to mb (b is a positive constant) and can bring the car to a terminal velocity Vinfinity. a) given that the racing car starts from rest, show that it reaches a speed of Vinfinity/2 in time [math]\frac{v_{\infty}log3}{2(b-a)}[/math] b) at this point the e…

I'm looking for a non-textbook about maths wich suits pre-university level (that's not to say I don't want anything challenging). I would quite like to learn about something entirely new to me, such as chaos theory or cryptogoraphy. What can you recomend?

Say you have three sides of a right triangle that form an arithmetic sequence. The only possible one is 3-4-5. Prove this.

can someone help me solve these two equations (and please explain)? log9 (q) = log12 (p) = log18 (q + p) what is q and what is p? and.... sinA + sinB = (square root 2) over 2 cosA + cosB = (square root 6) over 2 sin(A + B) = ? Thanks in advanced!

which outcome has a greater occurence: having 4 rolls to land a six with one die, or having 36 rolls to land (2) 6's with 2 die?

I can't figure out how to do this algerbically, though I know the answer: There are 2 numbers that their sum is 100; and the product of the number is 24 times 100. The answers are 40 and 60. I have 2 equations: [math]x + y = 100[/math] and [math]xy=2400[/math], but I'm not exactly sure how to put it together and get the answers. Can anybody help me?

Can someone give me an example of Moore's Law used in real life? Thanks

I am wondering if anyone could factor this for me? [math]a^{4} + 2b^{4} + c^{4} - 2a^{2}c^{2} - 2a^{2}b^{2} + 2b^{2}c^{2}[/math]

Hi, I'm suggesting a new reinforcement learning algorithm applied in my case on robots, please see: http://www.compactech.com/kartoun/articles/html/Kartoun_RA_2005_September_3_2005_Accepted.htm'>http://www.compactech.com/kartoun/articles/html/Kartoun_RA_2005_September_3_2005_Accepted.htm I would like to describe the algorithm more scientifically; define it mathematically much better than described in the paper. I'm asking for guidance of how to prove an algorithm, for example in the form of convergence or superiority. How can I demonstrate advantages or disadvantages of an algorithm mathematically? How can I prove convergence or divergence? How …

I've just saw an article online about finding a recursive expression for pi through a formula of centripetal force. It doesn't tell you how though! Anyone's ever heard of this?

http://www.newscientist.com/article.ns?id=dn6151 Has he gone over the hill? Or do you still have faith in him still?

Your town has decided to drill a well to increase its water supply. As the town engineer, you have determined that a water tower will be necessary to provide the pressure needed for distribution, and you have designed the system shown below. The water is to be pumped from a 300-ft well through a vertical 4-in. pipe into the base of a cylindrical tank 20ft in diameter and 25 ft high. The base of the tank will be 60 ft above ground. The pump is a 3-hp pump, rated at 1650 ft*lb/sec. How long will it take to fill the tank the first time? (Include the time it takes to fill the pipe) (62.5 lb = 1 ft^3) I tried to do them separtely then add the work to fill the pip and tank …

Can someone help me with this problem? A 8.48 g sample of an unknown organic compound containing only carbon, hydrogen, and oxygen was burned completely to produce 12.42 g of carbon dioxide and 5.08 g of water. Find the percentage of carbon, hydrogen, and oxygen in the compound. I just need to know how to get started, and what to do, my teacher confused herself on this one and no one in the class can do it.

If kx^2 - kx - 6 is divisible by both (x + 1) and (x + m), find the value of m. Given 2/x = y/3 = x/y , find x^3. One way to pack a 100 by 100 square with 10,000 circles, each of diameter 1, is to put them in 100 rows with 100 circles in each row. If the circles are repacked so that the centers of any three tangent circles form an equilateral triangle, what is the maximum number of additional circles that can be packed?