Question

write sin x + sin 5x as a product

Answer 1

= 2 sin 'semi-sum' cos 'semi-difference'

= 2 sin 3x cos 2x

Answer 2

\( \sin A + \sin B = 2 \sin \frac{A+B}{2} \cos \frac {A-B}{2}, where , A>B \)

Answer 3

This is one of the Prosthaphaeresis Formulas ( http://mathworld.wolfram.com/ProsthaphaeresisFormulas.html)

Answer 4

thanks!

Answer 5

Glad to help :)