Question

Question #a29a7

Answer 1

0

Explanation:

given (sin 20 - cos 110)(sin 20 + cos 110)

= `(sin 20)^2 - (cos 110)^2`

= `(sin 20)^2 - (cos 90+20)^2`

= `(sin 20)^2 - (-sin 20)^2`

= `sin 20^2 - sin 20^2`

= 0