Solving Fourier Series Prob: Need Help With Integral Parts

[math&science]

I've got parts of this problem but I'm stuck on some of the integration. See attached. Thanks!

 

[HallsofIvy]

First, since an interval is 0 to \pi what are you integrating over 0 to \pi/2[/tex]?<br /> <br /> Second, since cos x is positive from 0 to \pi/2 and negative from \pi/2 to \pi, you can replace |cos(x)| with <br /> cos(x) from 0 to \pi/2 and with -cos(x) for \pi/2 to \pi.

 

[math&science]

First, since an interval is 0 to \pi what are you integrating over 0 to \pi/2[/tex]?<br /> Second, since cos x is positive from 0 to \pi/2 and negative from \pi/2 to \pi, you can replace |cos(x)| with <br /> cos(x) from 0 to \pi/2 and with -cos(x) for \pi/2 to \pi.

<br /> <br /> I changed the interval I was integrating over b/c that&#039;s part of the equation. You can&#039;t integrate from -l to l so you change it to 0 to l where l is half of the fundamental period and instead of multiplying the integral by 1/l, I changed it to 2/l. Is it easier to just integrate from -l to l?