Q41 / 90 · JEE Main 2024 (29 Jan Shift 1) · Mathematics

If the points of intersection of two distinct conics x2+y2=4b and x216+y2b2=1 lie on the curve y2=3x2, then 33 times the area of the rectangle formed by the intersection points is _______.

Correct answer: 432

Solution

Given conics are x2+y2=4b and x216+y2b2=1.

The intersection point of these conics lie on y2=3x2.

So, putting y2=3x2 in both the conics.

⇒x2+3x2=4b, x216+3x2b2=1

⇒x2=b, b16+3bb2=1

⇒b16+3b=1

⇒b2+48=16b

⇒b2-16b+48=0

⇒b2-12b-4b+48=0

⇒b-4b-12

⇒b= 4, 12 ( b=4is rejected because curves coincide)

⇒b=12

⇒x=±12

⇒12+y2=48

⇒y=±6

Hence points of intersection are (±12,±6).

So, length and breadth of rectangle are 212 and 12. 

Figure

So, the area of rectangle is given by, A=212×12=483

⇒33A=483×33

⇒33A=432

Hence, the correct answer is 432.

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