Question

prove that sin 7 theta-sin 5 theta by cos 7 thete+cos 5 theta is equal to tan theta​

Answer 1

Step-by-step explanation:

LHS=apply sin c - sin d and cos c + cos d

=2cos(7theta+5theta/2)sin(7theta-5theta/2)/

2cos(7theta+5theta/2)cos(7theta-5theta/2)

=Cancel 2cos(7theta+5theta/2)

=tan(2theta/2)

Cancel 2

=tan theta

=RHS