general solution cos (4x-60)=sin2x [-90:90]

Solve cos(4x-60^@)=sin2x :
cos(4x-60^@)=sin2x
sin(4x+30^@)=sin2x
Take the inverse sine of both sides:
1. 4x+30=180-2x+360n where n is an integer.
6x=150+360n
x=25+60n
or
2. 4x+30=2x+360n
2x=-30+360n
x=-15+180n
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The general solution is x=25+60n for n an integer or x=-15+180n for n an integer.
On the interval [-90,90] the solutions are x=-35,-15,25,85
Here is the graph: the left side in black and the right side in red:

convert the scale from radian to degrees.