設F'(x)=f(x),f(x)為可導函數,且f(0)=1,又F(x)=xf(x)+x^2,求f'(x)和f(x)

設F'(x)=f(x),f(x)為可導函數,且f(0)=1,又F(x)=xf(x)+x^2,求f'(x)和f(x)

F(x)=xf(x)+x^2
F'(x)=f(x)+xf'(x)+2x
又F'(x)=f(x)
所以,f(x)=f(x)+xf'(x)+2x
則有:f'(x)=-2
則:f(x)=-2x+c
又f(0)=1,即:c=1
所以,f(x)=-2x+1,f'(x)=-2