NTA Abhyas JEE Main2020MathematicsParabolaPractice
The point of intersection of the tangent to the parabola y 2 = 4 x which also touches x 2 + y 2 = 1 2 is
Options
- A- 1 , 0
- B- 1 2 , 0
- C- 2 , 0
- D- 3 2 , 0
Correct answer
A. - 1 , 0
Step-by-step solution
Equation of the tangent to the parabola is y = m x + 1 m Equation of the tangent to the circle is y = m x ± 1 2 1 + m 2 For common tangent 1 m 2 = 1 2 1 + m 2 ⇒ m 4 + m 2 - 2 = 0 ⇒ m 2 = 1 ⇒ m = ± 1 ⇒ Equation of the tangents are y = x + 1 and y = - x - 1 ⇒ Point of intersection of these tangents is - 1 , 0