determine the maximum and minimum values of the function y=2cos2x-cos4x
Dear Student,
2cos2x-cos4x
=2 cos2x -2cos22x +1
=-2(cos2x-1/2)2 +3/2
minimum value occur when cos2x-1/2 will be maximum
=-2(-1-1/2)2 +3/2
=-3
and minimum value is 3/2
Regards