# Thread: f (of) X type problem...

1. ## f (of) X type problem...

Completely lost on this one! Not even sure where to start?

3. ## Re: f (of) X type problem...

OMG, ok thank you! I will try and plug in and do this on the problem.

4. ## Re: f (of) X type problem...

Notice that when h tends to zero (0) you will get the derivative of f(x)(By definition) , which is f'(x)=9x^2-1