To integrate this we need to use the chain rule, substituting cos2x = u Integral becomes: u2sin32x dxChain rule: dy/dx = du/dx dy/du du/dx = -2sin2x --> dx = -1/2sin2x du Substituting into the equation u2sin32x * -1/2sin2x du Simplifies to: -2u2sin22x duWe know that cos2x + sin2x =1 Integral = -2u2(1 - cos22x) du Substituting -> -2u2 + 2u4 duIntegrating this: -2( 1/3u3 - 1/5u5) + c Substituting u back into the equation: cos52x/10 - cos32x/6 + c