Question

设函数y=f(x)在x=x0处可导（有图）

Answer 1

1)原式=f'(x0),这就是x0处导数的定义

2)原式=lim [f(x0+5h)-f(x0)+f(x0)-f(x0-3h)]/(5h)

=lim [f(x0+5h)-f(x0)]/(5h)+lim [f(x0)-f(x0-3h)]/(5h)

=f'(x0)+3/5*lim [f(x0)-f(x0-3h)]/(3h)

=f'(x0)+3/5f'(x0)

=8f'(x0)/5