y=xsiny的二阶导数是多少?

一阶导：d/dx y=d/dx(xsiny)dy/dx=siny+xd/dx(siny)=siny+xdy/dxcosy那么dy/dx(1-xcosy)=sinydy/dx=siny/(1-xcosy)二阶导：y/dx?=(dy/dxcosy(1-xcosy)-siny(-xsiny(dy/dx)-cosy))/(1-xcosy)?=(sinycosy+xsin?y/(1-xcosy)-cosy)/(1-xcosy)?（将dy/dx=siny/(1-xcosy)代入!）

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