SOLUTION: Find cos theta/2 exactly if tan theta= -7/12 and theta is in Quadrant IV.

Algebra ->  Trigonometry-basics -> SOLUTION: Find cos theta/2 exactly if tan theta= -7/12 and theta is in Quadrant IV.      Log On


   

Question 613555: Find cos theta/2 exactly if tan theta= -7/12 and theta is in Quadrant IV.
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Find cos theta/2 exactly if tan theta= -7/12 and theta is in Quadrant IV
using x in place of theta
tanx=-7/12
hypotenuse of reference angle in quadrant IV=√(7^2+12^2)=√193
cosx=12/√193
Using cos half-angle formula:
cos(x/2)=±√[(1+cosx)/2]
=√[(1+(12/√193)/2]