Question

What is `sin (21pi)/12`?

Answer 1

`- sqrt2/2`

Explanation:

Trig unit circle and trig table -->
`sin ((21pi)/12) = sin ((-3pi)/12 + (24pi)/12) = sin (- pi/4 + 2pi) =`
`= sin (-pi/4) = - sin (pi/4) = - sqrt2/2`