Verified Solution • 2025–26 Session moderate

QJEEM23Ma993c: JEE Main 2023 Mathematics - Class 12 JEEM23Ma993c Solution

lim⁡t→0(11sin⁡2t+21sin⁡2t + ... + n1sin⁡2t)sin⁡2t\mathop {\lim }\limits_{t \to 0} {\left( {{1^{{1 \over {{{\sin }^2}t}}}} + {2^{{1 \over {{{\sin }^2}t}}}}\, + \,...\, + \,{n^{{1 \over {{{\sin }^2}t}}}}} \right)^{{{\sin }^2}t}} is equal to

Multiple Choice Options

  • A n(n+1)2{{n(n + 1)} \over 2}
  • B n
  • C n 2^2 + n
  • D n 2^2

Step-by-Step Verified Solution

amp;lim⁡t→0(1cosec⁡2t+2cosec⁡2t+……..+ncosec⁡2t)sin⁡2tamp;=lim⁡t→0n((1n)cosec⁡2t+(2n)cosec⁡2t+……..+1)sin⁡2tamp;=n\begin{aligned}& \lim _{t \rightarrow 0}\left(1^{\operatorname{cosec}^2 t}+2^{\operatorname{cosec}^2 t}+\ldots \ldots . .+n^{\operatorname{cosec}^2 t}\right)^{\sin ^2 t} \\\\& =\lim _{t \rightarrow 0} n\left(\left(\frac{1}{n}\right)^{\operatorname{cosec}^2 t}+\left(\frac{2}{n}\right)^{\operatorname{cosec}^2 t}+\ldots \ldots . .+1\right)^{\sin ^2 t} \\\\& =\mathrm{n}\end{aligned}

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