Question

The equation of the directrix of the parabola $y^2+4y+4x+2=0$ is

• A. $x=-1$
• B. $x=1$
• C. $x=-\frac{3}{2}$
• D. $x=\frac{3}{2}$

Answer 1

The correct option is D $x=\frac{3}{2}$

The given equation can be written as ${(y+2)}^2=-4(x-\frac{1}{2})\Rightarrow Y^2=-4AX$

Now the equation of the directrix is $X=A$

Here $A=1$

$\Rightarrow x-\frac{1}{2}=1$

$\therefore x=1+\frac{1}{2}=\frac{3}{2}$