Sequence And Series Question 136

Question: The $ n^{th} $ term of series $ \frac{1}{1}+\frac{1+2}{2}+\frac{1+2+3}{3}+……. $ will be

[AMU 1982]

Options:

A) $ \frac{n+1}{2} $

B) $ \frac{n-1}{2} $

C) $ \frac{n^{2}+1}{2} $

D) $ \frac{n^{2}-1}{2} $

Show Answer

Answer:

Correct Answer: A

Solution:

Given series $ \frac{1}{1}+\frac{1+2}{2}+\frac{1+2+3}{3}+…… $ So $ n^{th} $ term of series is given by $ T_{n}=\frac{1+2+3+…….+n}{n}=\frac{\frac{1}{2}n(n+1)}{n}=\frac{n+1}{2} $



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