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JEE Mains · Maths · STD 11 - 8. sequence and series
The sum of the series \(1 + \frac{1}{{1 + 2}} + \frac{1}{{1 + 2 + 3}} + .......\) up to \(10\) terms, is
- A \(\frac{{18}}{{11}}\)
- B \(\frac{{22}}{{13}}\)
- C \(\frac{{20}}{{11}}\)
- D \(\frac{{16}}{{9}}\)
Answer & Solution
Correct Answer
(C) \(\frac{{20}}{{11}}\)
Step-by-step Solution
Detailed explanation
\({T_r} = \frac{1}{{1 + 2 + 3 + ... + r}} = \frac{2}{{r\left( {r + 1} \right)}}\)…
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