How do I integrate these? Sin^2(x) cos^2(x)?

Answer 1

since sin2x=2sinxcosx∫

∫sin²x*cos²x dx=1/4 ∫4sin²x*cos²x dx=1/4∫sin²2x dx=1/4∫1-cos4x /2 dx, sin²x=1-cos2x/2

Finally the answer would be x/8-sin4x/32 +c after you apply u-substitution.