Recent content by Username007

Okay, I got it. If the limit equals k and k>0, then \forallε>0\:\existsδ>0 (|x|<δ \rightarrow \left|\frac{f(x)-f(0)}{x-0}-k\right|<ε) implies (for ε=k/2) that \existsδ>0 (|x|<δ \rightarrow \frac{k}{2}<\frac{f(x)-f(0)}{x-0}<\frac{3k}{2}) But...

Homework Statement Proof that, If f is a function such that (1) f is differentiable at (open) the interval D, (2) D includes 0 and f(0)=0, and (3) for all x in D other than 0, f(x) and x have opposite signs Then f'(0)\leq0 Homework Equations None. The Attempt at a Solution I managed...

Hi everyone, I have posted one or two questions in classical physics, but I'm basically new here. I'm relatively new physics student. I've been studying physics in university about a year by no, although the interest in physics comes from far behind. I'm relatively good at maths, although...

If you decompose the normal force vector into two vectors (Nx and Ny) you will find that Ny does positive work while Nx does the same amount of work, but negatively.

This is a problem I've been looking to solve for some time. Homework Statement You must find a movement equation for an object in a gravitational field knowing traditional formulas of force and acceleration of gravity (see below).Homework Equations absolute value of the acceleration at a...

So, if the result of integration does not converge we can't establish the equality? (Thanks for you patience btw ^_^)

And, thanks :)

It doesn't, that's the point. Why can I use integration by parts and "say" that \int\frac{e^x}{x}dx equals a sum that does not converge?

Here I used integration by parts to try to solve an integral (I got it wrong, it seems), I know this has no "simple" solution, but, can anyone explain me exactly what did I do wrong? Here is what I did...