Find the exact value of sin15° by using a sum or difference formula.

Answer 1

sin15 = sin(45-30) = sin45cos30 - cos45sin30 = (sqr2/2)(sqr3/2) - (sqr2/2)(1/2)

= (sqr6 -sqr2)/4

check the answer with a calculator

(sqr6 -sqr2)/2 = about .26

sin 15 = about .26