Question

How do I find the EXACT value of the following.

1. sin (pi/12) cos (5 pi/12) + cos (pi/12) sin (5pi/12)
2. cos (2pi/3 - pi/6)
3. sin (5pi/12)

For number two I know you have to do something with identiden

Answer 1

1. \(\sin (\pi/12 + 5\pi/12)\) using: sin (a+b)

Answer 2

\[\sin \left( A+B \right)=\sin A \cos B+\cos A \sin B\]\[\cos \left( A-B \right)=\cos A \cos B+\sin A \sin B\]

Answer 3

Ah yes I just got that one.
It's 1!

Answer 4

Actually it's 1.2247

Answer 5

For number three is it 3.647?

Answer 6

I just got number 4.