Express each of the following as a product.

1. sin 10x + sin 6x


2. sin 7x – sin 3x


3. cos 7x + cos 5x


4. cos2x – cos 4x


1. = 2


=2


=2


Using,


sin( A +B)= sinA cos B + cosA sinB


= 2


= 2


= 2cos5x sin2x


Using,


sin( A - B)= sinA cos B - cosA sinB


= 2


= 2


= 2


Using,


cos (A + B) = cosAcosB – sinAsinB


4.= -2


= -2


= 2sin3x sinx


Using,


cos (A - B) = cosAcosB+ sinAsinB


1