Which of the following series represents the function f(x)=∫0x1−e−ttdtf(x) = \int_0^x \frac{1-e^{-t}}{t} dtf(x)=∫0xt1−e−tdt?
∑n=1∞(−1)n−1xnn⋅n!\sum_{n=1}^{\infty} \frac{(-1)^{n-1} x^n}{n \cdot n!}∑n=1∞n⋅n!(−1)n−1xn
∑n=1∞(−1)n−1xnn!\sum_{n=1}^{\infty} \frac{(-1)^{n-1} x^n}{n!}∑n=1∞n!(−1)n−1xn
∑n=1∞xnn⋅n!\sum_{n=1}^{\infty} \frac{x^n}{n \cdot n!}∑n=1∞n⋅n!xn
∑n=0∞(−1)nxnn!\sum_{n=0}^{\infty} \frac{(-1)^n x^n}{n!}∑n=0∞n!(−1)nxn