Question

Sin (A + B). Cos (A-B) + Sin (A-B) cos (A + B) =​

Answer 1

Step-by-step explanation:

=cos(90-A-B).cos(A-B)+sin (A+B).sin(90-A-B)

=cos square (90-2B)+sin square (90-2B)

= cos square a+sin square a=1

(let 90-2B be as 'a')