Establish the identity sin ( π/2 + Ø) = cos Ø

Question

Which of the following four statements establishes the identity?

 

A.) sin ( π/2 + Ø) = sin π/2 sin Ø+cos π/2 cos Ø=(0)sinØ+(1)cosØ=cosØ

B.) sin ( π/2 + Ø) = sin π/2 sin Ø-cos π/2 cos Ø=(1)cosØ-(0)sinØ=cosØ

C.) sin ( π/2 + Ø) = sin π/2 cos Ø-cos π/2 sin Ø=(1)cosØ-(0)sinØ=cosØ

D.) sin ( π/2 + Ø) = sin π/2 cos Ø+cos π/2 sin Ø=(1)cosØ+(0)sinØ=cosØ

Answer 1

D is the correct application of the formula for sine of the sum of two arguments (angles).