Sequence And Series Question 565

Question: If $ y=1+\frac{x}{1,!}+\frac{x^{2}}{2,!}+\frac{x^{3}}{3,!}+……\infty $ , then $ x= $

Options:

A) $ {\log_{e}}y $

B) $ {\log_{e}}\frac{1}{y} $

C) $ e^{y} $

D) $ {e^{-y}} $ !

Show Answer

Answer:

Correct Answer: A

Solution:

$ y=1+\frac{x}{1\ !}+\frac{x^{2}}{2\ !}+\frac{x^{3}}{3\ !}+……=e^{x}\Rightarrow x={\log_{e}}y $ .