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JEE-Main 2024
27-01-24 S2
Question
If $2 \tan ^2 \theta-5 \sec \theta=1$ has exactly 7 solutions in the interval $\left[0, \frac{n \pi}{2}\right]$, for the least value of $n \in N$ then $\sum_{\mathrm{k}=1}^{\mathrm{n}} \frac{\mathrm{k}}{2^{\mathrm{k}}}$ is equal to :
Select the correct option:
A
$\frac{1}{2^{15}}\left(2^{14}-14\right)$
B
$\frac{1}{2^{14}}\left(2^{15}-15\right)$
C
$1-\frac{15}{2^{13}}$
D
$\frac{1}{2^{13}}\left(2^{14}-15\right)$
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
Solution
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Mathematics
Medium
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