Question

Prove that
sin(75°+alpha).sin(75°-alpha)-cos(15°+alpha).cos(15°-alpha)=0​

Answer 1

Step-by-step explanation:

sin(75°+alpha)sin(75-alpha)-cos(15+alpha)cos(15-alpha)

=sin(75+alpha)cos(90-75+alpha)- cos(15+alpha)sin(90-15+alpha)

=sin(75+alpha)cos(15+alpha)- sin(75+alpha)cos(15+alpha)

=0

Answer 2

see the attachment

hope it helps