Skip to content
dronacharya.ai
← JEE Main 2026 · 5 Apr · Shift 2
MathematicsSingle correct+4 / -1Question 12 of 75

JEE Main 2026 · 5 Apr · Shift 2, Mathematics question 12

Let the directrix of the parabola P:y2=8xP:y^2=8x, cut xx-axis at the point A. Let B(α,β)B(\alpha,\beta), α>1\alpha>1, be a point on P such that the slope of AB is 3/53/5. If BC is a focal chord of P, then six times the area of ΔABC\Delta ABC is :

Choose one option
Answer and worked solution

Official answer: B

Setup. a=2a=2, so A=(−2,0)A=(-2,0). Take B=(2t2,4t)B=(2t^2,4t).

Slope. 4t2t2+2=35\dfrac{4t}{2t^2+2}=\dfrac35 gives 3t2−10t+3=03t^2-10t+3=0, so t=3t=3 or 13\tfrac13. Since α>1\alpha>1, t=3t=3 and B=(18,12)B=(18,12).

Focal chord. C has parameter −1t=−13-\tfrac1t=-\tfrac13, so C=(29,−43)C=\left(\tfrac29,-\tfrac43\right).

Area.
12∣−2(12+43)+18(−43)+29(−12)∣=12⋅1603=803.\tfrac12\left|-2\left(12+\tfrac43\right)+18\left(-\tfrac43\right)+\tfrac29(-12)\right|=\tfrac12\cdot\tfrac{160}3=\tfrac{80}3.

Six times: 160.

(B)

Topics:Parabola