NTA Abhyas JEE Main2020MathematicsParabolaPractice
If the equation of the tangent at the point P 3,4 on the parabola whose axis is the x -axis is 3 x - 4 y + 7 = 0, then the distance of the tangent from the focus of the parabola is
Correct answer
2.5
Step-by-step solution
Slope of the tangent is 3 4 = tan θ Slope of the focal chord through P 3,4 is tan 2 θ = 2 tan θ 1 - t a n 2 θ i.e. tan 2 θ = 2 3 4 1 - 9 16 = 24 7 Equation of the focal chord through P is y - 4 = 24 7 x - 3 Focus is S 11 6 , 0 Distance of the focus from the tangent is 3 11 6 - 4 0 + 7 3 2 + 4 2 = 5 2 = 2 . 5