Question

The equation of tangent at P(- 4, - 4) on the curve x² = - 4y is ______.

Options

• 2x - y + 4 = 0

• 2x + y - 4 = 0

• 3x - y + 8 = 0

• 2x + y + 4 = 0

Answer 1

The equation of tangent at P(- 4, - 4) on the curve x² = - 4y is 2x - y + 4 = 0.

Explanation:

We know that equation of tangent of curve

x² = 4 y at (x₁, y₁) is

xx₁ = 2(y + y₁)

∴ Equation of tangent of curve x² = - 4y at (-4, -4) is

- 4x = - 2(y - 4)

⇒ 2x = y - 4

⇒ 2x - y + 4 = 0