# Thread: Find the limit, as h -> 0, of [ f(h) - f(-h) ] / h

1. ## Find the limit, as h -> 0, of [ f(h) - f(-h) ] / h

Hello,

I'm struggling with this calculation:

lim (f(h)-f(-h))/h
h->0

These were given in the assignment:
f(0) = -3
f'(0) = 5

I've tried basically everything and am at a loss. Thank you if you can help me solve the exercise.
Paula.

2. Originally Posted by paula12345
Hello,

I'm struggling with this calculation:

lim (f(h)-f(-h))/h
h->0

These were given in the assignment:
f(0) = -3
f'(0) = 5

I've tried basically everything and am at a loss. Thank you if you can help me solve the exercise.
Paula.
Rewrite:

lim (f(h)-f(-h))/h
h->0

= lim (f(0+h)-f(0-h))/h
h->0

Now use the definition f'(x) to continue....

3. Originally Posted by Subhotosh Khan
Rewrite:

lim (f(h)-f(-h))/h
h->0

= lim (f(0+h)-f(0-h))/h
h->0

Now use the definition f'(x) to continue....
Am I missing something or do we need to know what f(x) is?

4. No, you only need the derivative of f at x= 0.