How do you verify the identify (1−sinθ)(1+sinθ)=cos2θ?
1 Answer
Aug 27, 2016
We will use the following well known identities:
sin2(θ)+cos2(θ)=1 a2−b2=(a+b)(a−b)
With those, starting from the left hand side:
=12−sin2(θ)
=(sin2(θ)+cos2(θ))−sin2(θ)
=cos2(θ)