Question

How do you use half angle formula to find `sin 22.5`?

Answer 1

Trig identity: `2sin^a = 1 - cos 2a`

`2(sin 22.5)^2 = 1 - cos 45` = 1 - (sqr2)/2 = 0.293

`sin^2 (22.5) = 0.146 -> sin (22.5) = 0.38`