Question
Question: If the point P(2, –2) is the one end of the focal chord PQ of the parabola y<sup>2</sup> = 2x then s...
If the point P(2, –2) is the one end of the focal chord PQ of the parabola y2 = 2x then slope of the tangent at Q is
A
–2
B
2
C
½
D
–1/2
Answer
2
Explanation
Solution
Equation of tangent at (2, –2)
y (–2) = x + 2
–2y = x + 2
2y + x + 2 = 0
m = – ½
m¢ = (slope at Q) = 2
mm¢ = –1 (due to focal chord)