Mathematics

Let f(n) denote the maximum number of right triangles determined by n coplanar points. Prove f(n)/(n^2) --> infinity as n-->infinity and f(n)/(n^3) --> 0 as n-->infinity.

Just likes to say thanks to you lot for answering my dumb (and sometimes intelligant) questions on the maths forums over the last few months. Thanks to you lot I may just get the B I need to get into Bristol uni (to do Biochemistry, not maths thankgod).

hi anyone knows program for plotting domains of complex variable? such as: 1<|f(z)|<=3 or |arg(z)|<(Pi/4) or even something like this one: f(z)=z^3, |z|<=2, Im(z)>=0 thanks

won't be too many more question, got my last maths exam monday but you help would be much appreciated. Solve for [math]0 \leq x <360[/math] [math]2cos(x + 50)^o = sin(x + 40)^o[/math] and [math]2cosx+sinx = 5[/math]

Please use the attachment. Find the shaded area of the triangle. i've made some changes and i think the diagram cann't be any more clear than this. attachment.doc

Problem Solved...

Hi, me and my mate were talking about uni and stuff. he does computer science at imperial. and this came up. its the famous eight queen problem "All you have to do is put eight queens on a chess board so that none of them are attacking each other." sounds easy rite. but believe me, i can manage only 7. apparently he had to write a program to find a solution to this problem. and yes there are solutions. So now, I dont want anyone to cheat or look it up on the web. I would just like to know how a mathematician would go about solving this. I was thinking about using matrices. a 8by8 matrice. but then i dont know what to do with it. anyway if anyone can find a so…

What the hell is this equation? Aproaching zero, y became fractalized (?). It goes up and down in incredible way.

exactly as the topic says... any ideas plz?

Don't know whether you've all noticed, but there's an encyclopedia module included in this version of vbPortal (which is the portal system we use for vBulletin). I have a few ideas to create a mathematical encyclopedia section (there's already a science encyclopedia with 1 entry in it ) to link to various key ideas (e.g. famous theorems, matrix operations, definitions of important functions, etc), a bit like MathWorld but on a smaller scale. This way, if someone has a question in the future that we've already answered using a theorem, we don't have to go and state the theorem every time, just point a link to it. Any thoughts/suggestions?

This is a quick and dirty guide to using mimeTeX on the forums. The aim is to make it a little bit easier for you all to post proper mathematics, and not have to mess around with bracketing and things like that. The first thing to note, is that when you use the math tag to encompass an equation, there cannot be any spaces in the text. Otherwise, your equation will not render properly. Instead, you must use a tilde (~). The second thing is, because mimeTeX is essentially a front-end for TeX, this means that syntaxically, the language is quite complex. This is for a good reason; it is very hard to properly typeset mathematics, and a great amount of detail is needed …

y = psinx + qcosx passes through the points (0,3) and (pi/4,0). Find the values of p and q. Using formula on the coordinates i've got y = 3 + 12x/pi so psinx + qcosx = 3 + 12x/pi but then where? only 2 identities i need for this course is sinx/cosx = tanx and (sinx)^2 + (cosx)^2 = 1 but i cant see how i can use these

I came to thinking whether there is such thing as randomness in math. So far, from my studies of math I can only see strictly defined patterns with definite outcomes. For example, take the pseudo random number generation in computer science. Those numbers are nothing but the outcome of many factors taken into the equation. So, the question is if math is supposed to explain (or come from) the nature, wouldn't this contradict the thermodynamics law of tendency to strive to randomness? Or, if there is nothing random about math, is it fair to say that there is no such thing as occurance by a pure chance in nature?

Take a four digit positive number A, reverse the digits to make number B show that A^2 - B^2 is always divisible by 99 example: A=3785 B=5873 first question in my analysis exam today , dont know why.

Everything has a pattern e.g. if a coin is flipped there is an equal chance of tails and heads if the coin is fair. If coin flipped 10 times you would expect 5 heads and 5 tails, in reality, randomness stops this from happening. However, if the coin is flipped a million times then there will be a 50:50 split between heads and tails. Does this mean in theory that you could travel in time as there must be a pattern to everything? And as you got further away from present it would be more accuracy as randomness would have less of an effect? THIS IS ONLY IN THEORY!! Are there any problems, in theory, to this?

Thanks dave for the last piece of information. I find myself stuck on a question about triangles. What is the side length of an equilateral triangle if the area is 1732 cm squared. What is the equation? I'm missing something? Thanks in advance

go to http://hyperphysics.phy-astr.gsu.edu/hbase/alg2.html#ap scroll down to the part on algebra practice equations. x = (b(e-c))/(a-bd) so a can't = bd or the equation becomes undefined. put x + 0 = x + 0 and you get NaN. what's NaN? Does that mean all real numbers? put x + 1 = x + 0 and you get -Infinity... I don't get it. I thought it was null set. put x + 0 = x + 1 and you get Infinity... I don't get that either. I thought it was null set.

i just signed up; i'm a 4th-yr student @ U of Victoria, BC, canada & I just want to talk math with people

I need to solve the integral by the Lobatto quadrature. Could you please promt me any programs (if it exists), literature, links about the Lobatto quadrature? Thanks.

Here's a little maths exercise that I found quite interesting. Assume there is a test for a fatal illness that is proven to be 98% accurate (a wrong diagnosis is given only 1 in 50 times) and the innacuracy is equal for both false negatives and false positives. Also assume that 0.5% of the tested population have the illness (1 in 200). If you are tested and your doctor tells you that you have contracted the illness what is the likelyhood that this diagnosis is correct? Is it worth demanding a second opinion? I'll post the answer and proof after we've had some responses.

Help I;m not very good in math and I need to find the answers to this question. A steel tie bar 7 m long, 10 cm wide and 1.25 cm thick is subjected to a tensile force of 133 000 N. cALCULATE; A. The stress produced in the bar B. The strain produced C. The amount the bar is stretched in cm. How do i find the answer?

I have a friend who mention to me today that he thinks that all irrational numbers are no more than concepts, since they don't seem to have any physical representation to describe themselves. If this is true, then what place does 0 and infinity fall in? It seem 0 is got to be a number since it's not irrational, but he said that there is no representation for 0 either. What's your opinion on the subject?

hope you guys can help. high school, especially the 9th grade seems to have ended an eon ago and I need your help. I know there is a way to descipher, read and write(?) bar codes manually. if anybody knows the method or a website that shows how to do it, I'd appreciate that tremendously.

[math]x=2[/math]

Ok. you have a n by n grid of squares. ie. made out of n^2 small squares. all u have to do is find the total number of squares of all sizes. If u want to , you can extend the problem into a rectangle of n by m squares . Also find the number of possible rectangles(rectangles also includes squares)