KCET2007MathematicsParabola
The focus of the parabola y=2 x²+x is
Options
- A(0,0)
- B( 1 2 , 1 4 )
- C(- 1 4 , 0 )
- D(- 1 4 , 1 8 )
Correct answer
C. (- 1 4 , 0 )
Step-by-step solution
The given equation of parabola is y=2 x²+x ²+ x 2 = y 2 x²+ x 2 + 1 16 = y 2 + 1 16 (x+ 1 4 )²= 1 2 (y+ 1 8 ) where x+ 1 4 =X and y+ 1 8 =Y On comparing with X²=4 A Y , we get A= 1 8 focus of Eq. (i) is (0, 1 8 ) i.e. X=0, Y= 1 8 x+ 1 4 =0, y+ 1 8 = 1 8 x=- 1 4 , y=0 Focus of given parabola is (- 1 4 , 0 ) .