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

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

anonymous · Answer

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

anonymous · Answer

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

anonymous · Answer

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

anonymous · Answer

Actually it's 1.2247

anonymous · Answer

For number three is it 3.647?

anonymous · Answer

I just got number 4.