## finding first and second derivatives of fk=f(xk) for k=i-2 etc

Hi guys,
I'm having a bit of trouble figuring out this question for what the lecturer thinks that we should have covered in high school, but I'm sure we have not.

the questions goes:
From 5 values fk= f(xk), k=i-2, i-1, i, i+1 and i+2, write down expressions for first and second derivatives in the point x=xi. Consider accuracies O(Dx) and O(Dx2). where D is delta.
If I also had k=j-2 how would I find the partial first and second derivatives?

Can I just get some tips/hints on how to start this question as I have no idea at the moment.

Any help would be great

cheers