Question

The length of the latus - rectum of the parabola y² + 8x – 2y + 17 = 0 is :

A. 2 

B. 4 

C. 8 

D. 16

Answer 1

Option : (C)

Given equation of the parabola is y² + 8x - 2y + 17 = 0

⇒ y² - 2y + 17 = - 8x 

⇒ y² - 2y + 1 = - 8x - 16 

⇒ (y - 1)² = - 8(x + 2) 

Comparing with standard form of parabola (y - a)² = - 4b(x - c) we get, 

⇒ 4b = 8 

We know that,

The that the length of the latus rectum is 4b.