Sequence And Series Question 573

Question: $ (1+3){\log_{e}}3+\frac{1+3^{2}}{2,!}{{({\log_{e}}3)}^{2}}+\frac{1+3^{3}}{3,!}{{({\log_{e}}3)}^{3}}+…..\infty = $

[Roorkee 1989]

Options:

A) 28

B) 30

C) 25

D) 0

Show Answer

Answer:

Correct Answer: A

Solution:

$ S={\log_{e}}3+\frac{{{({\log_{e}}3)}^{2}}}{2!}+\frac{{{({\log_{e}}3)}^{3}}}{3!}+……..+3{\log_{e}}3+\frac{{{(3{\log_{e}}3)}^{2}}}{2!}+\frac{{{(3{\log_{e}}3)}^{3}}}{3!}+…. $ $ =({e^{{\log_{e}}3}}-1)+({e^{3{\log_{e}}3}}-1)=(3-1)+(3^{3}-1)=28 $ .



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