JEE Main 2021 — Parabola Question with Solution
From: JEE Main 2021 (Online) 31st August Evening Shift
Question
A tangent line L is drawn at the point (2, 4) on the parabola y2 = 8x. If the line L is also tangent to the circle x2 + y2 = a, then 'a' is equal to ___________.
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Show full solutionCorrect answer: 2
Correct answer
2
Step-by-step explanation
tangent of y2 = 8x is y = mx +
P(2, 4) 4 = 2m +
m + = 2 m = 1
tangent is y = x 2
x + y + 2 = 0 ...... (1)
(1) is also tangent to x2 + y2 = a
So,
a = 2
P(2, 4) 4 = 2m +
m + = 2 m = 1
tangent is y = x 2
x + y + 2 = 0 ...... (1)
(1) is also tangent to x2 + y2 = a
So,
a = 2
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