Question

show that:

sin square 11° - cos square 79° =0​

Answer 1

LHS = sin²11-cos²79

= sin ²(90-79) - cos ²79

= cos²79 - cos ²79

=0

LHS = RHS

Answer 2

LHS = sin²11-cos²79
= sin ²(90-79) - cos ²79
= cos²79 - cos ²79
=0