Using the definition of a Taylor polynomial, find T3(x) of degree 3 for the function:

f(x)=ln(x-1) centered at point X0=2.

Find the remainder R3 = f - T3 in LaGrange form. Compute T3(2.1) and estimate R3(2.1).

I know the Taylor series formula, and I can write out the an arbitrary amount of terms for the function, but what exactly is is asking me to do?