请问如何对数列x^n/(n*n!)求和(n趋于无穷大),如1 + x + x^2/(2!×2)+ x^3/(3!×3).
请问如何对数列x^n/(n*n!)求和(n趋于无穷大),如1 + x + x^2/(2!×2)+ x^3/(3!×3)...,
如题.都困扰很久了:(
Actually there is no elementary derivative.Have to use exponential integral Ei(x) to define the complex elements.Still thanks.