Solve 6 cos ( 2 β ) = 6 cos 2 ( β ) − 4 for all solutions 0 ≤ β < 2 π β =

Answer 1

You can graph 6cos(2x) and 6cos(2x) - 4 and trace the intersection points by pressing "2nd" then "calc" and clicking on "intersection". This is where those to functions will be equal to each other. Since you are only looking for solutions from x = 0 to x = 2pi, you can change your window to x min = 0 and x min = 2pi to find the intersection points only on that interval.