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Limits Continuity and Differentiability question

2025 · 3 Apr · Shift 2 · Q46
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Limits Continuity and Differentiability question

2025 · 3 Apr · Shift 2 · Q46

JEE MainMathematicsLimits Continuity and DifferentiabilityNumerical+4 / −1
If lim⁡x→0(tan⁡xx)1x2=p\mathop {\lim }\limits_{x \to 0} \left(\frac{\tan x}{x}\right)^{\frac{1}{x^2}}=px→0lim​(xtanx​)x21​=p, then 96log⁡ep96 \log _{\mathrm{e}} p96loge​p is equal to ‾\underline{\hspace{2cm}}​
Numerical answer
View written solutionFree

Correct answer: 32

  1. We need to evaluate p=lim⁡x→0(tan⁡xx)1x2.p=\lim_{x\to 0}\left(\frac{\tan x}{x}\right)^{\frac{1}{x^2}}.p=limx→0​(xtanx​)x21​.

  2. This is of the form 1∞1^{\infty}1∞, so take natural logarithm: ln⁡p=lim⁡x→01x2ln⁡(tan⁡xx).\ln p=\lim_{x\to 0}\frac{1}{x^2}\ln\left(\frac{\tan x}{x}\right).lnp=limx→0​x21​ln(xtanx​).

  3. Use the standard expansion of tan⁡x\tan xtanx near x=0x=0x=0: tan⁡x=x+x33+O(x5).\tan x=x+\frac{x^3}{3}+O(x^5).tanx=x+3x3​+O(x5). Therefore, tan⁡xx=1+x23+O(x4).\frac{\tan x}{x}=1+\frac{x^2}{3}+O(x^4).xtanx​=1+3x2​+O(x4).

  4. Now use ln⁡(1+u)=u+O(u2)for small u.\ln(1+u)=u+O(u^2)\quad \text{for small }u.ln(1+u)=u+O(u2)for small u. Here, u=x23+O(x4).u=\frac{x^2}{3}+O(x^4).u=3x2​+O(x4). So, ln⁡(tan⁡xx)=x23+O(x4).\ln\left(\frac{\tan x}{x}\right)=\frac{x^2}{3}+O(x^4).ln(xtanx​)=3x2​+O(x4).

  5. Hence, ln⁡p=lim⁡x→01x2(x23+O(x4))=13.\ln p=\lim_{x\to 0}\frac{1}{x^2}\left(\frac{x^2}{3}+O(x^4)\right)=\frac{1}{3}.lnp=limx→0​x21​(3x2​+O(x4))=31​. Thus, p=e1/3.p=e^{1/3}.p=e1/3.

  6. Now compute: 96ln⁡p=96⋅13=32.96\ln p=96\cdot \frac{1}{3}=32.96lnp=96⋅31​=32.

Therefore, the required integer is 32.\boxed{32}.32​.

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