Question

Find the value of ( 1+cosA) (1-cosA)

Answer 1

sin^2 A

Explanation:

first expand the trigonometry

1(1-cosA)+cosA(1-cosA)

=1-cosA+cosA-cos^2 A

= 1-cos^2 A

from trigonometric identity sin^2 A + cos^2 A= 1

sin^2 A= 1- cos^2 A

=sin^2 A