Maths-
General
Easy
Question
The normal y = mx – 2am – am2 to the parabola y2 = 4ax subtends a right angle at the origin, then-
- m = 1
- m =
- m = 2
- m =
The correct answer is: m =
Standard equation of the normal at P(at2, 2at) is y + xt = 2at + at3.
Hence t = – m. This meets the parabola again at Q whose parameter is – t – or m +
coordinates of Q are a , 2a
Since
m = is one of the choices.
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