Chapter 23, Problem 6P

Employ Eq. (23.9) to determine the first derivative of $y=2x^4-6x^3-12x-8$ at $x=0$ based on values at $x_0=-0.5$, $x_1=1$, and $x_2=2$. Compare this result with the true value and with an estimate obtained using a centered difference approximation based on $h=1$.