Question

Half-Angle Identities: How would i solve sin(13pi/12)? Don't know what to do with the 13, since it is not part of the Unit Circle.

Answer 1

Consider that 13 = 9 + 4

Answer 2

9pi/12 and 4pi/12 should be on the unit circle.

Answer 3

you can use the identity: \[
\sin(x+y) = \sin(x)\cos(y) + \sin(y)\cos(x)
\]

Answer 4

i have to do that with in the equation?
the sinx/2

Answer 5

Okay then try the halfangle formula.