设z=f(x,y)二阶连续可导,且=x+1,fx’(x,0)=2x,f(0,y)=sin2y,则f(x,y)=_________.

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问题 设z=f(x,y)二阶连续可导,且=x+1,fx(x,0)=2x,f(0,y)=sin2y,则f(x,y)=_________.

选项

答案f(x,y)=([*]+x)y+x2+sin2y

解析=(x+1)y+φ(x),
由fx(x,0)=2x得φ(x)=2x,即=(x+1)y+2x,
再由=(x+1)y+2x得z=(+x)y+x2+h(y),
由f(0,y)=sin2y得h(y)=sin2y,故f(x,y)=(+x)y+x2+sin2y.
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