sinx^2*cos2x求导?

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sinx^2*cos2x求导?

sinx^2*cos2x求导?
sinx^2*cos2x求导?

sinx^2*cos2x求导?
sinx^2*cos2x
=(sin²x)'cos2x+sin²x(cos2x)'
=2sinxcosxcos2x+sin²x(-2sin2x)
=sin2xcos2x-2sin²xsin2x
=sin2x(cos2x-2sin²x)
=sin2x(1-4sin²x)

sinx^2*cos2x导数
=cosx^2*2x*cos2x-sinx^2*sin2x*2
=2xcosx^2*cos2x-2sinx^2*sin2x

(sinx^2*cos2x)'=(sinx^2)'*cos2x+sinx^2*(cos2x)'
=2sinxcosx*cos2x-2sinx^2*sin2x
=2sinxcosx(cos2x-2sinx^2)
=sin2x(1-4sinx^2)

原式=cosx²*(x²)'cos2x+sinx²(-sin2x)(2x)'
=2xcosx²cos2x-2sinx²sin2x

=1/4·2sin2·cos2x·(2x)' =1/4·2sin2·cos2x·2 =1/2·(2sin2·cos2x) =1/2· sin4x y=2sinx*cosx^3-2cosx*sinx^3 =1/2