Recent content by stefaneli

Thanks man.:)

Singularities on real axis?

I have a problem with choosing a contour for integration... Can someone explain to me when to use a keyhole contour and when a semi-circle? Thanks...:)

Thanks...it helped me:)

To be exact... \rho \rightarrow 0+ The solution I've written is correct for sure.:)

Homework Statement I don't know how to find a limit, and it's bothering me for a few hours now. Can someone help me? j - imaginary unit Homework Equations \lim_{\rho \to 0}{\frac{\frac{\sqrt{2}}{2}(-1+j)+\rho \exp(j\theta)}{(\frac{\sqrt{2}}{2}(-1+j)+\rho \exp(j\theta))^2+...

I was wondering if it's possible to know the difference between order of numerator and order of denumerator of open loop transfer function W(s) using Nyquist criterion ('stable' poles/zeros are bothering me; basically is there a way to find out a number of poles and zeros of W(s))? I hope I've...

Thanks tiny-tim. I don't know how I haven't noticed. Stupid.:) But can it be done the way I started? Just curious.

Homework Statement I need to find the sum of a given infinite series when |x|<1 (which is the radius of this series) Homework Equations [SIZE="3"]\sum_{n=1}^{∞}(-1)^{n+1}\frac{x^{2n+1}}{4n^2-1} The Attempt at a Solution I've tried to do the following: [SIZE="3"]S'(x) =...

Thanks. (Mt. Kilimanjaro-size thanks)

I didn't want you to try, but to give the opinion if the substitution could work or not. Can you post the solution?

I wouldn't insist on using L.m., if I don't have to. I agree that your approach is better, but I must use L.m. So the substitution isn't the right way? It's not correct? Thanks.

ellipsoid: \left(x-3\right)^{2}\over{3}+y^{2}\over{4}+z^{2}\over{5} = 1 surface: 3x+4y^{2}+6z + 6=0 Can I use substitution u = y^{2}? Ellipsoid will than transform to paraboloid and parabolic cylinder to plane. And after that I would maximize (Lagrange multipliers)...

Oh, sorry. Distance between point on ellipsoid and surface should be max. The equation is correct.

That's a new way of looking at the problem, but I don't see how can I solve this. How to find that minimum distance that I'm going to maximize?