Recent content by ensten

A particle of mass m is inside a long, narrow tube which rotates a constant angular velocity ω in the horizontal plane. (This means that you see the tube from the top of the figure and not from the side.) At time t = 0 is the particle on the radial distance a from the rotational axis and the...

Homework Statement Find f(t) for: 2\int_{0}^{t}f'(u)sin(9(t-u)du +5cos(9t), t\geq0 The Attempt at a Solution F(s)=2\frac{9(sF(s)-f(0))}{s^2+81}+\frac{5s}{s^2+81} At this point i don't know what to do with f(0) since there are no initial conditions. What do I do with it?

I don't quite understand how to do that. I tried the sum function at wolframalpha and I get that it doesn't converge.

\sin(n \frac{3\pi}{2}) changes for different n's. Example: -1, 0 and 1. So I don't know how to simplify that. However \sin(n \pi) will always be 0 for all n.

Homework Statement h(x)=\left\{\begin{matrix} 9+2x , 0<x<\pi\\ -9+2x , -pi<x<0 \end{matrix}\right. \\ Find \ the \ sum \ of \ the \ Fourier \ series \ for \ x=\frac{3\pi}{2} and\ x=\pi \\ The \ Fourier \ series \ is: \\ h(x)=9+\pi + \sum_{n=1}^{inf}...