Mathematics · 2019
JEE Main · 8 April 2019, Shift 2 · Q69
The sum Σ_k=1^20 k 1/2^k is equal to:
The sum $\displaystyle \sum_{k=1}^{20} k \frac{1}{2^k}$ is equal to :
Official answer
(1)
$\displaystyle 2-\frac{11}{2^{19}}$
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JEE Main 2019 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.