For slowly convergent sequences, the Aitken extrapolation formula (3.52) can greatly accelerate the convergence. Use the following algorithm:
$$
\begin{aligned}
&x_{1}=g\left(x_{0}\right) \\
&x_{2}=g\left(x_{1}\right)
\end{aligned}
$$
$x_{3}=$ Aitken extrapolate of $x_{0}, x_{1}$, and $x_{2}$
$$
\begin{aligned}
&x_{4}=g\left(x_{3}\right) \\
&x_{5}=g\left(x_{4}\right)
\end{aligned}
$$
$x_{6}=$ Aitken extrapolate of $x_{3}, x_{4}$, and $x_{5}$
Continue this process in the same manner. Apply it to the following iterations:
(a) $x_{n+1}=2 e^{-x_{n}}, \quad x_{0}=0.8$
(b) $\quad x_{n+1}=\frac{0.9}{1+x_{n}^{4}}, \quad x_{0}=0.75$
(c) $x_{n+1}=6.28+\sin \left(x_{n}\right), \quad x_{0}=6$