Proofs Definition and 671 Threads

Where can I find some good problems involving finding proofs? I want to see how far I can go as it's relatively new to me...

Hey I have 2 quick questions... 1) Any advice for proofs, I am just starting with them, and wondering how I can make good proofs, i know very little about the now :| anything that other people expierienced while starting proofs would be great, (its grade 12 algebra) 2) Anyone know where...

Let f:X->Y be a function 1) Given any subset B of Y, prove that f(f^-1(B)) is a subset of B 2) Prove that f(f^-1(B))=B for all subsets B of Y if and only if f is surjective Help anybody?

Hello everyone, I'm a budding theoretical physicist and mathematician, all throughout my education I've been taught about mathematical objects, relation between objects, Proofs, etc. Never have I been taught HOW to actually learn math. I've put together a website with all the lessons on how...

Ok, I've seen many proofs of this, all being the same, but the closest I could find online was here: http://freespace.virgin.net/mark.davidson3/IMS2121/buoyancy/Buoyancy.html Basically the idea is you mess around with the formulas for pressure and hey bingo. However, I have one question - the...

Thanks in advance for any help, I'm trying to understand epsilon-delta proofs, and the various sites I've found so far aren't helping that well. I know that epsilon is referring to a small number >0, and delta traditionally refers to a number > epsilon, but I'm not quite sure of why this...

How do I show |Rez - Rez0|<E whenever 0<|z-z0|<D is true, where E and D are real number greater than 0, and z is obviously a complex number? In other words, proving that the lim of Rez (as z approaches z0)=Rez0.

Im looking for some proofs on the rationality of pi. I also want to know what some people think about it.

Know any 'nice' proofs in maths? Or know an alternative and simpler/nicer proof to common method employed? Post here ==>

I'm sure most of you already know this. The real point of the thread is finding different ways of approaching it. You see, I have a friend who refuses to accept what seems to me to be so obvious: .9 repeating (infinite 9s after the decimal) is exactly equal to the whole number 1. Here are the...

Do mathematical proofs exist, of things that we are not sure exist, especially those, that do not have observational confirmed data?

I know this is below most of those that peruse these forums, but I've been giving myself an ulcer trying to figure these silly things out. The first problem starts out as (1-sin^2(x))(1+tan^2(x))=1 and I've got it down to (sin^2(x)/tan^2(x))-sin^2(x)=1 but from there I've got no idea...

Ok, I know about the search for supersymmetric partner particles (sparticles) and the tests on gravity variance at small scales, but what other tests are there that can be used to add proof to superstring theory?

I understand how to use such things as product rules, quotient rules, parts by integration, but it bothers me I don't really have a deeper understanding of it. My book offers rather rigorous proofs, they are all pretty much: assume this to be this and let this be that so it must equal this...

I'm having trouble with two parallelogram proofs 1) PQRS is a parallelogram and T is any point inside the parallelogram. Prove that triangle TSR + triangle TQP = 1/2 parallelogram PQRS 2) ABCD is a quadrilateral whose area is bisected by the diagonal AC. Prove that BD is bisected by AC...

Hello, First I will post the question that I am working on. I am not good at proofs (even elementry proofs such as these ones). I was wondering if someone could take a look at my work and perhaps confirm whether my proofs are adequate and/or make some suggestions. First I will start...

I was having some serius problems when proving some of the questions where we are given, let's say, a rectangle, there is one diagnol, and the other diagonal is connected to a line that is in a ratio, and the diagnal connects to the point that divides that line. The concept is combined with...

[SOLVED] Geometry Proofs. Hello, I am currently taking a second year mathematics course in geometry at university. I have to do quite a few proofs and I am not used to doing proofs much less geometry proofs -last time I took geometry was when I was in grade 10 and that was over ten years...

Hi! I'm new to the forums. I'm taking an introduction to physics class this semester and I've been having some difficulty with it. Oh, I also wanted to let you know that it's been a while since I've taken calculus or any other math class for that matter. But I need physics to graduate. Anywho...

Hello everyone, My first post on these forums and I was wondering if I could have some assistance/direction with a problem: Prove that if p is a prime number and a and b are any positive integers strictly less than p then a x b is not divisible by p. The first thing I thought to myself...

Backward induction Is there any proof that involve the use of back induction besides the proof of AM>=GM ? It is the only example I've come across that use back induction.