Let the line L : 2 x + y = α pass through the point of the intersection P (in the first quadrant)of the…

Let the line L:2x+y=α pass through the point of the intersection P(in the first quadrant)of the circle x2+y2=3 and the parabola x2=2y. Let the line L touch two circles C1 and C2 of equal radius 23. If the centres Q1 and Q2 of the circles C1 and C2 lie on the y-axis, then the square of the area of the triangle PQ1Q2 is equal to _________.

Solution

Given: x2+y2=3 and x2=2y

y2+2y3=0

y+3y1=0

y=1,-3 Rejected as it gives imaginary value of x

y=1

x=2

P2,1

Now, P lies on the line 2x+y=α.

22+1=α

α=3

For circle C1Q1 lies on y-axis.

Let Q10,β and R1=23 (given)

Line L act as tangent so applying the condition of tangency

P=r

β33=23

β3=6

β3=6, -6

β=9, -3

So, Q10,9 & Q20,-3

ArΔPQ1Q2=12200193111

ArΔPQ1Q2=12212

ArΔPQ1Q2=62

ΔPQ1Q22=72

Asked in: JEE Main 2024 (01 Feb Shift 1)

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