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
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