Recent content by anonymity

I'm at a loss on this question...my troubles seem to be algebraic or that I'm simply missing something.x' = \mu - x2 +4x4 my method for these questions has basically been to do everything required to draw bifurcation diagram bar drawing the actual diagram itself (ie, find equilibria, what...

hello, I am going through the first chapter (a review chapter) of a second-course book in ODEs, and can't seem to remember how to re-write higher order DEs into a system of first order linear ODEs, and my old textbook only shows this for second order equations... The question is: "Write the...

Started writing this yesterday. Hoping for some constructive critique. As far as what I have to say about it...It is not finished, and I have not yet gotten to talking about the program I am interested in yet, just background stuff about me so far (really looking to find out if I'm going too...

Prove that if g\circf is surjective, then g must be surjective. I know that one valid proof of this statement is acquired via the contrapositive, what I am not sure of is if the following proof is flawed (if it is, please say why): Suppose z\inZ. Since g \circ f is surjective, there exists...

Hey everyone, I'm a sophomore math and ME major (long story), and as the title suggests, want to take part in a math REU program this summer. I have taken calculus I-III, am currently taking a first course in proofs (Set Theory and Logic), applied linear algebra, and introductory ODEs. Next...

Hey everyone, I'm taking intro ODEs right now, and am taking intro PDEs next semester. I would like to know what i should review from calc III for this course. I took calc III over the summer at a community college and didn't learn very much, if I'm being honest with myself. I think I am...

Okay that makes an incredible amount of sense... thanks ><

It's just sort of weird thinking of the implication out of its dry logical context... I don't see how that proves the implication in the logical form (ie if i drew it out on a truth table). edit: after reading my post, I think a good replacement for "dry" would be "un-applied" edit 2.0: I...

but in the actual proof, how do you know that P(k) "IMPLIES" p(k + 1), aside from the fact that (hopefully) the answer via assumption and the given formula coincide (in the basic summation example) =|

Hello, I have a question about inductive reasoning... Earlier this week my intro proofs class went over the logical structure of induction, and an example. The example was a proof of \Sigmai = n*(n + 1)/2 My main issue is the assumption that "p(k)" is true. What if it's not? I asked this in...

You are either missing information, or neglecting to post it. A vector has a magnitude and a direction. What you posted for a and b has the magnitude part down, but is missing direction. Is this all you were given? (this will likely be moved -- but I'm not an admin so oh well for now)

No it was a real mess of statements. What I posted was actually just part of the final product (but that contradiction held all of the power, so to speak). I do remember something along the lines of that in it though. Thanks for confirming =]

If the negation of an implication is a contradiction, the implication is a tautology. Is this correct? Because if the negation is never true, then it must be a tautology...No? For example, I am working on a problem that, after a whole bunch of other stuff, the negation of my statement is P...

Very clever. Thank you ^

How did you write that matrix in physicsforum's latex?! And by nonzero they just mean it's not 0 0 0 0 Thanks for responding hallsofivy