JEE PYQ: Parabola Question 21
Question 21 - 2019 (09 Jan Shift 1)
Axis of a parabola lies along $x$-axis. If its vertex and focus are at distance 2 and 4 respectively from the origin, on the positive $x$-axis then which of the following points does not lie on it?
(1) $(5, 2\sqrt{6})$
(2) $(8, 6)$
(3) $(6, 4\sqrt{2})$
(4) $(4, -4)$
Show Answer
Answer: (2)
Solution
Vertex $(2, 0)$, focus $(4, 0)$. Parabola: $(y-0)^2 = 4 \times 2(x-2) \Rightarrow y^2 = 8(x-2) = 8x - 16$. Check $(8,6)$: $36 = 64 - 16 = 48$. $36 \neq 48$. So $(8, 6)$ does not lie on it.
BETA
