- #1

haha1234

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## Homework Statement

Suppose that f is differentiable at x . Prove that ƒ(x)=lim[h→0] [itex]\frac{ƒ(x+h)-ƒ(x-h)}{2h}[/itex]

## Homework Equations

## The Attempt at a Solution

I think that it may be proved by first principle,but I cannot rewrite the limit into the form of lim[h→0] [itex]\frac{ƒ(x+2h)-ƒ(x)}{2h}[/itex]

So how can I solve this question?

THANKS