PreCalc : Find the Exact Value of the Expression
posted by Phil HELP NEEDED ASAP .
Find the exact value of the expression without a calculator:
sin(3π/4+5π/6)
I've done:
sin(9π/12 + 10π/12)
=sin(19π/12)
What do I do now? Im confused if that would just be the answer or what? Wouldnt the answer be numerical?

sin(19π/12) = sin(3π/2 + π/12) = cos(π/12)
Now use the halfangle formula to evaluate that. 
Thank you!

tan(15)