Question 576936
1. find the value of cos 7pi/6 sin 3 pi/4 + sin 7pi/6 cos 3pi/4 
--------------
Use the sum of angles formula for sines.
sin(A+B) = sin(A)cos(B) + sin(B)cos(A)
----
--> sin(3pi/4 + 7pi/6)
= sin(23pi/12)
-----------