=cos[cos^2(x^3+x)]×[cos^2(x^3+x)]'=cos[cos^2(x^3+x)]×2cos(x^3+x)[cos(x^3+x)]'=-cos[cos^2(x^3+x)]×2cos(x^3+x) sin(x^3+x) ×(x^3+x)'=-(3x^2+1)cos[cos^2(x^3+x)]sin2(x^3+x)