Question

2 cos 5a sin 2a=cos 7a -cos3a .prove the equation​

Answer 1

Step-by-step explanation:

2cos5asin2a formula is sin(a+b)-sin(a-b)

sin(5a+2a)-sin(5a-2a)

sin7a-sin3a

therefore 2cos5asin2a=sin7a-sin3a