NTA Abhyas JEE Main2020MathematicsParabolaPractice
The equation of the tangent to the parabola y 2 = 4 x whose slope is positive and which also touches x 2 + y 2 = 1 2 is
Options
- Ay = x + 1
- By = 2 x + 1
- Cx + y = 2
- Dy = 4 x + 1 2
Correct answer
A. y = x + 1
Step-by-step solution
Tangent to parabola is y = m x + 1 m Tangent to 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