In this paper, f (x) = (e ^ x-e ^ - x) / 2 is expanded into a power series of X, and its convergence interval is obtained

In this paper, f (x) = (e ^ x-e ^ - x) / 2 is expanded into a power series of X, and its convergence interval is obtained

e^x=1+x+x^2/2!+x^3/3!+.x^n/n!+.|x|