So I am currently a math undergraduate (senior though) taking an introduction partial differential equations. We are using the PDE book by Farlow (Dover reprint). It seems to be a solid book though my professor does diverge from the methods used in it fairly regularly (like not making...
I used the trig identity sin(x)sin(y)=\frac{cos(x-y)-cos(x+y)}{2}. So my term becomes ##A_m \int \left(\frac{ cos(0)-cos(2m\pi x)}{2}\right) =A_m\left(\frac{1}{2}+\frac{sin(2m\pi)}{4m\pi} \right)## Is this not acceptable?
I managed to obtain $$A_m=\frac{4}{\pi}\left(\frac{1}{m}\right)$$ but I...
1. Find the Fourier sine expansion of \phi(x)=1. This was posted in Calculus and Beyond thread, but I realized that this thread may be more appropriate.
2. The attempt at a solution.
I start with \phi(x)=A_1sin(\pi x)+A_2sin(2\pi x)+\cdots+A_nsin(n\pi x), and then add multiply by A_msin(m\pi x)...
1. Find the Fourier sine expansion of \phi(x)=1
.2. Homework Equations .
In the lecture the professor worked his stuff from scratch so I was trying to do it like his example.3. The Attempt at a Solution .
I start with \phi(x)=A_1sin(\pi x)+A_2sin(2\pi x)+\cdots+A_nsin(n\pi x), and then add...