Question

Two tangents are drawn from (-2, -1) to the parabola y² = 4x. If ‘α‘ is the angle between them, then tanα =

• A. 3
• B. 1/3
• C. 2
• D. ½

Answer 1

Answer: (A)

3

Answer 2

Angle between the tangents drawn to the parabola

S≡ y² – 4ax from (x₁, y₁) is given S ≡ y² – 4x, (x₁,y₁) =(-2, -1).

∴ tanα = $\left| \frac { \sqrt { \mathrm { S } _ { 11 } } } { \mathrm { x } _ { 1 } + \mathrm { a } } \right| = \left| \frac { 3 } { - 2 + 1 } \right| = 3$ .