= 2 sin(2x)sin(2x)cos(2x)-sin(x)sin(x)cos(2x)-sin(x)cos(x)sin(2x)

=2[ 1-cos^2(2x)]cos(2x)-[ 1-cos(2x)]/2 cos(2x)- 1/2[ 1-cos^2(2x)]

= 2 [cos (2x)-cos 3 (2x)]-[cos (2x)-cos 2 (2x)]/2-1/2 [1-cos 2 (2x)]

= 3/2 cos (2x)-2 cos 3 (2)-1/2+cos 2 (2)

Let cos 2x=p, then the equation is-2p3+3/2 * p+p2-1/2 = a (-1

Then find out the extreme point, maximum value and minimum value of the above-mentioned univariate cubic equation, compare them respectively, draw a graph and see the value of A.