Question

How do you use the half angle identity to solve sin 165°, cos 165° and tan 165° ?

Answer 1

First figure out what `165^@` is half of.

(It is half of `2xx165^@`)

Now, for `sin(165^@)` We need to know whether `sin165^@`;is positive or negative.

(`165^@` is in quadrant 2, so it's sine is positive.)

Now use the formula.

Repeat for cosine and tangent.