Hello everybody

Given the Lagrange polynomial with the table:

$\displaystyle \begin{tabular} {|c|c|c|c|}

\hline

x & 8.3 & 8.6 & 8.7 \\

\hline

f(x) & 17.56492 & 18.50515 & 18.32091 \\

\hline

\end{tabular}$

Find $\displaystyle P_2(x)$ for $\displaystyle x = 8.4$, the actual error and the bound of error for the function $\displaystyle f(x) = x \ln x$

Ok now I've found $\displaystyle P_2(x)$ and I'm approximating $\displaystyle P_2(8.4)$ which from my polyinomial is 17.877155 (close enough I think).

But I don't know how to find the bound of error using the remainder term! Anyone please show me the steps at least. Thanks in advance.