Double-angle and half-angle identiies [see attachment] question2

The double angle identity for cosine is

so the half angle identity is

We picked the negative sign because our angle is in the second quadrant, negative cosine.

I used the identity

I substituted in there cosine of 30 degrees

Looks like choice d

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)

2 x 503

step-by-step explanation:

its 1006