problem with half angle identity problem

[cotfw]

I am supposed to find the exact value of sin(15 deg).

I thought I would approach it like this:

sin(15) = √(1-cos(30))/2

Since cos(30) is (√3)/2, and 1 is equal to 2/2, I thought the above would become √(2-√3)/4

But this is wrong. Do you know what I did wrong?

 

[cotfw]

nvm i realized that the answer I got is equal to the correct answer.