Parabola 2 Question 6

6. Tangent and normal are drawn at P(16,16) on the parabola y2=16x, which intersect the axis of the parabola at A and B, respectively. If C is the centre of the circle through the points P,A and B and CPB=θ, then a value of tanθ is

(2018 Main)

(a) 12

(b) 2

(c) 3

(d) 43

Show Answer

Answer:

Correct Answer: 6. (c)

Solution:

  1. Equation of tangent and normal to the curve y2=16x at (16,16) is x2y+16=0 and 2x+y48=0, respectively.

A=(16,0);B=(24,0)

C is the centre of circle passing through PAB

i.e.

C=(4,0)

Slope of PC=160164=1612=43=m1

Slope of PB=1601624=168=2=m2

tanθ=m1m21+m1m2

tanθ=43+2143(2)tanθ=2



NCERT Chapter Video Solution

Dual Pane