Posted by james on .
What are the steps for solving this?
Directions Use the quadratic formula to solve the equation in the interval [0,2PI). Then use a graphing utility to approximate the angle x.
4cos^2x4cosx1=0
thanks.

precal 
bobpursley,
quadratic equation?
cosx= (4+sqrt(16+4))/8
graph y=4cos^2 x  4cosx + 1 and note where it crosses the y=0 axis.