Question

数学高手帮我整一下这道证明题吧!详细点哈呵呵谢啦

Answer 1

f'(x)

=lim(y->0) [f(x+y) -f(x)]/y

=lim(y->0) [f(x)f(y) -f(x)]/y

=lim(y->0) f(x)[f(y) -1]/y

=lim(y->0) f(x)[{1+yf(y)} -1]/y

=lim(y->0) f(x)*[f(y)]/y

=f(x)