，
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

f(x)的导数公式是什么，你让别人去查吗？别人顶多只告诉你C代码怎么写！

我试验了一下，
f(3.2) = 0.845456
f(2.73682) = -0.906911
f(3.6702) = 0.999738
f(-256.413) = 1
不收敛