題目 7. (10 points) Recall that the hyperbolic tangent function tanhx=ex−e−xex+e−x, x∈R\tanh x=\frac{e^x-e^{-x}}{e^x+e^{-x}},\ x \in \mathbb{R}tanhx=ex+e−xex−e−x, x∈R is one to one and has the inverse function f(x)=tanh−1xf(x)=\tanh^{-1}xf(x)=tanh−1x. Find the Maclaurin series of f(x)=tanh−1xf(x)=\tanh^{-1}xf(x)=tanh−1x. 解答