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设函数y=y(x)由方程y=xsiny所确定,求y'(0)与y''(0)

题目详情
设函数y=y(x)由方程y=xsiny所确定,求y'(0)与y''(0)
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答案和解析
y=xsiny
对x求导:y'=siny+xy'cosy
故y'=siny/(1-xcosy)
x=0时,有y=xsiny=0*siny=0
所以y'(0)=sin0/(1-0)=0
y"=[y'cosy(1-xcosy)-siny(-cosy+xy'siny)]/(1-xcosy)^2
故y"(0)=[0cos0-sin0(-cos0+0)/(1-0)^2=0