AJ L. answered 04/29/23
Patient and knowledgeable Precalculus Tutor
Use the half-angle identities sin2x = [1-cos(2x)]/2 and cos2x = [1+cos(2x)]/2:
sin2x·cos2x
= [1-cos(2x)]/2 * [1+cos(2x)]/2
= [1-cos2(2x)]/4
= sin2(2x)/4
= [[1-cos(2(2x))]/2]/4
= [1-cos(4x)]/8
Hope this helped!
AJ L.
I'm afraid that answer is incorrect. You forgot to double 2x in the angle. The answer should be (1/8)(1-cos(4x))04/29/23