Question

The point on the parabola$x - 2 y + 5 = 0$is

• A. $( - 1 / 2,2 )$
• B. $( 1 / 2 , - 2 )$
• C. $( 2 , - 1 / 2 )$
• D. $( - 2,1 / 2 )$

Answer 1

Answer: (B)

$( 1 / 2 , - 2 )$

Answer 2

Let point be $( h , k )$ . Normal is $y - k = \frac { - k } { 4 } ( x - h )$ or

$- k x - 4 y + k h + 4 k = 0$

Gradient $\left( \frac { 1 } { 2 } , - 2 \right)$

Trick: Here only point $\left( \frac { 1 } { 2 } , - 2 \right)$ will satisfy the parabola $y ^ { 2 } = 8 x$