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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 17 March 2021, Shift 1, Maths Q72

Question 72 of 90 in this shift, Maths question 12 of 30, Section A.

Which of the following is true for y(x)y(x) that satisfies the differential equation dydx=xy−1+x−y\frac{dy}{dx}=xy-1+x-y ; y(0)=0y(0)=0 :
  1. (1)y(1)=e−12−1y(1)=e^{-\frac{1}{2}}-1Official answer
  2. (2)y(1)=e12−1y(1)=e^{\frac{1}{2}}-1
  3. (3)y(1)=e12−e−12y(1)=e^{\frac{1}{2}}-e^{-\frac{1}{2}}
  4. (4)y(1)=1y(1)=1

Official answer

Option 1

NTA final key.

Same idea in other shifts

Asked 15× in all
  1. 4 Apr 2026, Shift 1 · Q20Let y=y(x)y=y(x) be the solution of the differential equation dydx=(1+x+x2)(1−y+y2)\frac{dy}{dx}=(1+x+x^2)(1-y+y^2), y(0)=12y(0)=\frac12. Then (2y(1)−1)(2y(1)-1) is equal toMediumSingle correct
  2. 8 Apr 2024, Shift 1 · Q13Let y=y(x)y=y(x) be the solution of the differential equation (1+y2)etan⁡xdx+cos⁡2x (1+e2tan⁡x)dy=0(1+y^2)e^{\tan x}dx+\cos^2x\,(1+e^{2\tan x})dy=0, y(0)=1y(0)=1. Then…MediumSingle correct
  3. 9 Apr 2024, Shift 1 · Q11The solution curve, of the differential equation 2ydydx+3=5dydx2y\frac{dy}{dx}+3=5\frac{dy}{dx}, passing through the point (0,1)(0,1) is a conic, whose…MediumSingle correct
  4. 27 Jan 2024, Shift 1 · Q13Let x=x(t)x=x(t) and y=y(t)y=y(t) be solutions of the differential equations dxdt+ax=0\dfrac{dx}{dt}+ax=0 and dydt+by=0\dfrac{dy}{dt}+by=0 respectively,…MediumSingle correct
  5. 29 Jan 2024, Shift 1 · Q26If the solution curve y=y(x)y=y(x) of the differential equation (1+y2)(1+log⁡ex)dx+x dy=0(1+y^2)(1+\log_e x)dx+x\,dy=0, x>0x>0 passes through the point (1,1)(1,1) and…MediumNumerical value
  6. 13 Apr 2023, Shift 1 · Q14Let y=y1(x)y=y_1(x) and y=y2(x)y=y_2(x) be the solution curves of the differential equation dydx=y+7\frac{dy}{dx}=y+7 with initial conditions y1(0)=0y_1(0)=0…EasySingle correct
  7. 26 Jun 2022, Shift 1 · Q30Let S=(0,2π)−{π2,3π4,3π2,7π4}S = (0, 2\pi) - \left\{\frac{\pi}{2}, \frac{3\pi}{4}, \frac{3\pi}{2}, \frac{7\pi}{4}\right\}. Let y=y(x)y = y(x), x∈Sx \in S, be the…HardNumerical value
  8. 29 Jun 2022, Shift 2 · Q9If y=y (x)y = y\,(x) is the solution of the differential equation (1+e2x)dydx+2(1+y2)ex=0\left(1 + e^{2x}\right)\frac{dy}{dx} + 2\left(1 + y^2\right)e^x = 0 and…MediumSingle 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.