Manipal MET2012MathematicsParabola
The equation of directrix of the parabola y^2+4 y+4 x+2=0 is
Options
- Ax=-1
- Bx=1
- Cx=- 3 2
- Dx= 3 2
Correct answer
D. x= 3 2
Step-by-step solution
We have, y^2+4 y+4 x+2=0 aligned & (y+2)^2+4 x-2 & =0 & (y+2)^2 & =-4 (x- 1 2 ) aligned Replace, y+2=Y, x- 1 2 =X We have, Y^2=-4 X This is a parabola with directrix at X=1 array lr & x- 1 2 =1 & x= 3 2 array