Verified Solution • 2025–26 Session moderate

QJEEM20Maa776: JEE Main 2020 Mathematics - Class 12 JEEM20Maa776 Solution

lim⁡x→0(tan⁡(π4+x))1x\mathop {\lim }\limits_{x \to 0} {\left( {\tan \left( {{\pi \over 4} + x} \right)} \right)^{{1 \over x}}} is equal to :

Multiple Choice Options

  • A 2
  • B 1
  • C ee
  • D ee 2

Step-by-Step Verified Solution

lim⁡x→0(tan⁡(π4+x))1x\mathop {\lim }\limits_{x \to 0} {\left( {\tan \left( {{\pi \over 4} + x} \right)} \right)^{{1 \over x}}}

This is 1 ∞\infty form.

= elim⁡x→0[tan⁡(π4+x)−1]×1x{e^{\mathop {\lim }\limits_{x \to 0} \left[ {\tan \left( {{\pi \over 4} + x} \right) - 1} \right] \times {1 \over x}}}

= elim⁡x→0[1+tan⁡x1−tan⁡x−1]×1x{e^{\mathop {\lim }\limits_{x \to 0} \left[ {{{1 + \tan x} \over {1 - \tan x}} - 1} \right] \times {1 \over x}}}

= elim⁡x→0[2tan⁡xx(1−tan⁡x)]{e^{\mathop {\lim }\limits_{x \to 0} \left[ {{{2\tan x} \over {x\left( {1 - \tan x} \right)}}} \right]}}

= e2lim⁡x→0[tan⁡xx×1(1−tan⁡x)]{e^{2\mathop {\lim }\limits_{x \to 0} \left[ {{{\tan x} \over x} \times {1 \over {\left( {1 - \tan x} \right)}}} \right]}}

= e2lim⁡x→0[1×1(1−0)]{e^{2\mathop {\lim }\limits_{x \to 0} \left[ {1 \times {1 \over {\left( {1 - 0} \right)}}} \right]}}

= e2

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