Cos^2(beta)-sin^2(beta)=1-2sin^2(beta)?

2sin2beta

#1

cos^2(beta)-sin^2(beta)=1-2sin^2(beta) ?

Answer:

cos^2(beta)-sin^2(beta)+2sin^2(beta)=1
cos^2(beta)+sin^2(beta)=1
which is a trigonometric identity, true for every beta