Answer:
see explanation
Explanation:
Using the trigonometric identity
sin²x + cos²x = 1 ⇒ cos²x = 1 - sin²x
Consider the left side
← multiply numerator/denominator by (1 + sinA)
=
← expand denominator using FOIL
=

=
← cancel cosA on numerator/ denominator
=
= right side , thus proven