# Calculating <cos^2(theta)>

1. Jan 26, 2012

What is the expectation value of cosine squared, namely <cos^2(t)>?

2. Jan 26, 2012

### Tarantinism

cos2x = (1+cos(2x))/2

Integration leads to 0,5 (averaged over the lenght)

3. Jan 26, 2012

### mathman

Another approach: cos2(x) + sin2(x) = 1. Both terms have the same average, so the average for cos2(x) = 1/2.