MHT CET202526 Apr 2025Morning ShiftMathematicsParabolaActual
The equation of the 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
Finding the directrix of the parabola defined by y²+4y+4x+2=0. Rewriting the equation by completing the square for the y-terms: y^2+4y+4 = -4x-2+4 , resulting in (y+2)^2 = -4x+2 . Factoring the right side yields (y+2)^2 = -4(x - 1/2) . This matches the standard form (y-k)^2 = -4a(x-h) , with vertex at (1/2, -2) and a=1 . The directrix for this left-opening parabola is x = h+a = 1/2 + 1 = 3/2 . Final answer: x = 3/2