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← JEE Main 2022 · 24 Jun · Shift 2
MathematicsSingle correct+4 / -1Question 8 of 90

JEE Main 2022 · 24 Jun · Shift 2, Mathematics question 8

A particle is moving in the xyxy-plane along a curve CC passing through the point (3,3)(3,3). The tangent to the curve CC at the point PP meets the xx-axis at QQ. If the yy-axis bisects the segment PQPQ, then CC is a parabola with

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Answer and worked solution

Official answer: A

Tangent meets the xx-axis at Q(x−yy′,0)Q\left(x-\dfrac y{y'},0\right).

Midpoint on the yy-axis. x+x−yy′=0x+x-\dfrac y{y'}=0, so dydx=y2x\dfrac{dy}{dx}=\dfrac y{2x}, giving y2=cxy^2=cx.

Through (3, 3). c=3c=3: y2=3xy^2=3x, whose latus rectum is 3 (focus (34,0)\left(\frac34,0\right)).

(A)