Question 955794
Find the exact value of the following: 

a) tan 65pi/6
65pi/6 = 60pi/6 + 5pi/6
10pi = 5*2pi
--> tan(5pi/6)
============
b) cos 150 (degrees)
Look up the unit circle.
------------------
c) sin 225 (degrees)
Look up the unit circle.
----------
d) sec 45pi/4
40pi/4 = 5*2pi
sec = 1/cos
Look up the unit circle.