Q. The directrix of the parabola $y^{2} + 4x + 3 = 0\$is
A) $x - \frac{4}{3} = 0$
B) $x + \frac{1}{4} = 0$
C) $x - \frac{3}{4} = 0$
D) $x - \frac{1}{4} = 0$
Explanation
(d)
Given $y^{2} = - 4\ \left( x + \frac{3}{4} \right)$
$\Rightarrow \ Y^{2} = \ - 4\ X,\$where$\ X = x + \frac{3}{4}\$and $Y = y\$
The equation of directrix of parabola is
$X = 1\ \Rightarrow \ \ \ x + \frac{3}{4} = 1\$
$\Rightarrow \ \ x - \frac{1}{4} = 0\$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.