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← JEE Main 2022 · 26 Jul · Shift 1
MathematicsSingle correct+4 / -1Question 7 of 90

JEE Main 2022 · 26 Jul · Shift 1, Mathematics question 7

If the function f(x)={log⁡e(1−x+x2)+log⁡e(1+x+x2)sec⁡x−cos⁡x,x∈(−π2,π2)−{0}k,x=0f(x)=\begin{cases}\dfrac{\log_e\left(1-x+x^2\right)+\log_e\left(1+x+x^2\right)}{\sec x-\cos x}, & x\in\left(\dfrac{-\pi}2,\dfrac\pi2\right)-\{0\}\\ k, & x=0\end{cases} is continuous at x=0x=0, then k is equal to :

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Answer and worked solution

Official answer: A

Numerator ln⁡(1+x2+x4)∼x2\ln(1+x^2+x^4)\sim x^2; denominator sin⁡2xcos⁡x∼x2\frac{\sin^2x}{\cos x}\sim x^2. Limit 1.

(A)