求y=tan[2x/(1+x^2)]的导数/>

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求y=tan[2x/(1+x^2)]的导数/>求y=tan[2x/(1+x^2)]的导数/>求y=tan[2x/(1+x^2)]的导数/>复合函数求导y''=sec^2[2x/(1+x^2)]*[2x/

求y=tan[2x/(1+x^2)]的导数/>
求y=tan[2x/(1+x^2)]的导数

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求y=tan[2x/(1+x^2)]的导数/>
复合函数求导
y'=sec^2[2x/(1+x^2)]*[2x/(1+x^2)]'
=sec^2[2x/(1+x^2)]*[(2x)'(1+x^2)-2x(1+x^2)]/(1+x^2)^2
=sec^2[2x/(1+x^2)]*[2(1+x^2)-4x^2]/(1+x^2)^2
=sec^2[2x/(1+x^2)]*2(1-x^2)/(1+x^2)^2

y=tan[2x/(1+x^2)]
所以,y'=sec^2 [2x/(1+x^2)]*[2x/(1+x^2)]'
=sec^2 [2x/(1+x^2)]*[(2x)'*(1+x^2)-2x*(1+x^2)']/(1+x^2)^2
=sec^2 [2x/(1+x^2)]*[2(1+x^2)-2x*2x]/(1+x^2)^2
=sec^2 [2x/(1+x^2)]*[2(1-x^2)/(1+x^2)^2]