(adsbygoogle = window.adsbygoogle || []).push({}); [SOLVED] Vanishing Integral

1. The problem statement, all variables and given/known data

http://mikef.org/files/phys_4242_hw5.pdf [Broken]

When does the integeral at the bottom of page 2 vanish? He says it vanishes when n'_y and n'_y have oppositive parity, but I think it always vanishes because n'_y - n'_y and n'_y + n'_y always have the same parity, so the integral over

cos(pi (n'_y - n'_y) y) and cos(pi (n'_y + n'_y) y)

should be the same.

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Vanishing Integral

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