Question

Express as a product Sin40+Sin20

Answer 1

Convert sin 7α + sin 5α as a product.

Solution:

sin 7α + sin 5α

= 2 sin (7α + 5α)/2 cos (7α - 5α)/2, [Since, sin α + sin β = 2 sin (α + β)/2 cos (α - β)/2]

= 2 sin 6α cos α

. Express sin 7A + sin 4A as a product.

Solution:

sin 7A + sin 4A

= 2 sin (7A + 4A)/2 cos (7A - 4A)/2

= 2 sin (11A/2) cos (3A)/2