x^3*sin2xy'=3x^2*sin2x+2x^3*cos2xy''=6x*sin2x+6x^2*cos2x+6x^2*cos2x-4x^3*sin2xy'''=6sin2x+12xcos2x+24xcos2x-24x^2sin2x-12x^2sin2x-8x^3cos2x=6sin2x+36xcosx-36x^2sin2x-8x^3cos2x