# Integration for fourier analysis

• May 4th 2013, 09:28 AM
aritech
Integration for fourier analysis
Hi,

Can someone please explain to me what is happening from step A to step B in the attached diagram of a Full-Wave rectified Waveform ??

Ok, he's applying the limits, but from where did he get the "-1"s?

Attached is also my working for those steps.

Any help would be appreciated.

Reference link: Full-Wave Rectified Waveform Help for Fourier Series, Computer Science, Homework Help - Transtutors.com
• May 4th 2013, 11:04 AM
johng
Re: Integration for fourier analysis
Hi,
It's simple plug in and evaluate, together with some elementary facts on cos. Here's further explanation:

Attachment 28243
• May 4th 2013, 11:10 AM
aritech
Re: Integration for fourier analysis
Thanks johng :) that was very helpful.
• May 4th 2013, 11:29 AM
aritech
Re: Integration for fourier analysis
Another quick question. Why should there be a minus in front of Vm/pi in step A ?

Also, cos(2n pi - pi) gives -1, but then there is the other -1 we found earlier, so wouldn't that make -2 in the last step ?? -1-1= -2