# Math Help - How to solve this question with a ti-89

1. ## How to solve this question with a ti-89

Let F be defined by f(x)=x^3. then f(x+h)-f(x-h)/2h=?

I plugged it into the calculator but it just gives me back the exact equation and not an answer?

2. ## Re: How to solve this question with a ti-89

Originally Posted by Shanker
Let F be defined by f(x)=x^3. then f(x+h)-f(x-h)/2h=?

I plugged it into the calculator but it just gives me back the exact equation and not an answer?
I've attached the screen-shot. Have a look at the input line. In this case the appropriate use of brackets is vital.