c语言初学者，数值分析课的牛顿迭代法题，求解法（自己想半天没思路）。
英文原题
(a) Apply the Newton-Raphson method to the function f(x) =
tanh(x2 - 9) to evaluate its known real root at x = 3. Use an initial
guess of x=3.2 and take a minimum of four iterations. (b) Did the
method exhibit convergence onto its real root? Sketch the plot with
the results for each iteration shown。
如果可以请麻烦解一下这道题，别的题目想跟着这个思路来做。
非常感谢
