Question

Show that sin 80° - sin 20º = cos 50°​

Answer 1

Answer:

Step-by-step explanation:

sin80=cos50+cos70

cosC+cosD=2cosC+D/2cosC-D/2

=2cos120/2cos-20/2

2cos60cos(-10)

=2×1/2cos10=cos10=sin(90-10)=sin80