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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 24 February 2021, Shift 2, Maths Q68

Question 68 of 90 in this shift, Maths question 8 of 30, Section A.

Let f(x)f(x) be a differentiable function defined on [0, 2] such that f′(x)=f′(2−x)f'(x)=f'(2-x) for all x∈(0,2)x\in(0, 2), f(0)=1f(0)=1 and f(2)=e2f(2)=e^2. Then the value of ∫02f(x) dx\int_{0}^{2}f(x)\,dx is :
  1. (1)1−e21-e^2
  2. (2)1+e21+e^2Official answer
  3. (3)2(1+e2)2(1+e^2)
  4. (4)2(1−e2)2(1-e^2)

Official answer

Option 2

NTA final key.

Chapter
Integrals
Idea tested
King's Property

Same idea in other shifts

Asked 18× in all
  1. 3 Apr 2025, Shift 2 · Q18The integral ∫0π8x dx4cos⁡2x+sin⁡2x\int_0^{\pi} \frac{8x\,dx}{4\cos^2 x + \sin^2 x} is equal toMediumSingle correct
  2. 8 Apr 2025, Shift 2 · Q18Let f(x)f(x) be a positive function and I1=∫−1212x f(2x(1−2x)) dxI_1 = \int_{-\frac{1}{2}}^{1} 2x\, f\big(2x(1-2x)\big)\,dx and…HardSingle correct
  3. 4 Apr 2024, Shift 1 · Q25If ∫0π/4sin⁡2x1+sin⁡xcos⁡xdx=1alog⁡e(a3)+πb3\int_0^{\pi/4}\frac{\sin^2x}{1+\sin x\cos x}dx=\frac{1}{a}\log_e\left(\frac{a}{3}\right)+\frac{\pi}{b\sqrt{3}}, where…HardNumerical value
  4. 5 Apr 2024, Shift 1 · Q10The value of ∫−ππ2y(1+sin⁡y)1+cos⁡2y dy\int_{-\pi}^{\pi}\frac{2y(1+\sin y)}{1+\cos^2 y}\,dy is :MediumSingle correct
  5. 5 Apr 2024, Shift 2 · Q25If f(t)=∫0π2x dx1−cos⁡2tsin⁡2xf(t) = \int_0^{\pi} \frac{2x\,dx}{1-\cos^2 t \sin^2 x}, 0<t<π0 < t < \pi, then the value of…HardNumerical value
  6. 1 Feb 2024, Shift 1 · Q10The value of the intergral ∫0π/4x dxsin⁡4(2x)+cos⁡4(2x)\int_0^{\pi/4}\frac{x\,dx}{\sin^4(2x)+\cos^4(2x)} equals :HardSingle correct
  7. 1 Feb 2024, Shift 2 · Q11The value of ∫−01(2x3−3x2−x+1)13 dx\int_{-0}^{1}(2x^3-3x^2-x+1)^{\frac{1}{3}}\,dx is equal to :MediumSingle correct
  8. 27 Jan 2024, Shift 1 · Q12If (a,b)(a, b) be the orthocentre of the triangle whose vertices are (1,2)(1, 2), (2,3)(2, 3) and (3,1)(3, 1), and I1=∫abxsin⁡(4x−x2) dxI_1=\int_a^b x\sin(4x-x^2)\,dx,…HardSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.