# URGENT: Normalization

#### ihaveaquestion

Joined May 1, 2009
314
Can someone please explain how the solution goes from the third from the last line to the 4th from the last line (where the cos^2 term is first introduced)?

I sort of need the answer asap, thanks a lot

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#### Peytonator

Joined Jun 30, 2008
105
Do you mean how to get from cos to cos^2? If so, use the identity

1+cos(2A) = 2*cos^2(A)

where 2A = beta*d*cos(theta)