来自蔡国松的问题
f(x)为非0函数高数f(x+y)=f(x)f(y)当x=0时的导数为1证明f(x)的导数等于f(x)
f(x)为非0函数高数f(x+y)=f(x)f(y)当x=0时的导数为1证明f(x)的导数等于f(x)


f(x)为非0函数高数f(x+y)=f(x)f(y)当x=0时的导数为1证明f(x)的导数等于f(x)
f(x)为非0函数高数f(x+y)=f(x)f(y)当x=0时的导数为1证明f(x)的导数等于f(x)
f(x+y)=f(x)f(y)
putx=y=0
f(0)=f(0)f(0)
f(0)=1
f'(x)=lim(y->0){[f(x+y)-f(x)]/y}
=lim(y->0)[f(x)f(y)-f(x)]/y
=f(x)lim(y->0)(f(y)-1)/y
=f(x)lim(y->0)(f(0+y)-f(0))/y
=f(x)f'(0)
=f(x)#