NTA Abhyas JEE Main2020MathematicsParabolaPractice
If two tangents drawn from the point P ( h , k ) to the parabola y 2 = 8 x are such that the slope of one of the tangent is 3 times the slope of the other, then the locus of point P is
Options
- A3 y 2 = 16 x
- B3 y 2 = 8 x
- Cy 2 = 32 x
- D3 y 2 = 32 x
Correct answer
D. 3 y 2 = 32 x
Step-by-step solution
Equation of tangent in slope form is y = m x + a m Let the tangent passes through P h , k ⇒ k = m h + a m ⇒ m 2 h - k m + a = 0 ⇒ m 1 + m 2 = k h  &  m 1 m 2 = a h Where, a = 2  &  m 2 = 3 m 1 ⇒ 4 m 1 = k h  &  3 m 1 2 = 2 h ⇒ 3 k 4 h 2 = 2 h ⇒ 3 y 2 = 32 x