AP EAMCET202119 Aug 2021Evening ShiftMathematicsParabolaActual
Find the equation of the parabola which passes through ( 6 , - 2 ) , has its vertex at the origin and its axis along the y - axis.
Options
- Ay 2 = 18 x
- Bx 2 = 18 y
- Cy 2 = − 18 x
- Dx 2 = − 18 y
Correct answer
D. x 2 = − 18 y
Step-by-step solution
As given, the vertex of the parabola is origin and it's axis is along the y - axis, So, the standard equation of the parabola with given conditions is, x 2 = - 4 a y     . . . 1 , as it passes through 6 ,   - 2 Hence, x 2 = - 4 a y   ⇒   6 2 = - 4 × a × - 2   ⇒   a = 36 8 = 9 2 So, substituting the value of a in equation 1 The equation is x 2 = - 18 y