AP EAMCET201726 Apr 2017Morning ShiftMathematicsParabolaActual
The equations of the parabola whose axis is parallel to the X -axis and which passes through the points (-2,1),(1,2)(-1,3) is
Options
- A18 y^2-12 x-21 y-21=0
- B5 y^2+2 x-21 y+20=0
- C15 y^2+12 x-11 y+20=0
- D25 y^2-2 x-65 y+36=0
Correct answer
B. 5 y^2+2 x-21 y+20=0
Step-by-step solution
Let, general equation of this parabola x=A y^2+B y+C It is given that, it passes through the points (-2,1),(1,2) and (-1,3) so, we get On solving Eqs. (i), (ii) and (iii), we get A= -5 2 , B= 21 2 and C=-10 Hence, equation of parabola aligned & x=- 5 2 y^2+ 21 2 y-10 & 2 x=-5 y^2+21 y-20 & 5 y^2+2 x-21 y+20=0 aligned