How do you verify the identify #(1-sintheta)(1+sintheta)=cos^2theta#?
1 Answer
Aug 27, 2016
We will use the following well known identities:
#sin^2(theta)+cos^2(theta) = 1# #a^2-b^2=(a+b)(a-b)#
With those, starting from the left hand side:
#=1^2-sin^2(theta)#
#=(sin^2(theta)+cos^2(theta))-sin^2(theta)#
#=cos^2(theta)#
