1)

The cartesian  coordinates of the point on the parabola y2=-16x, whose parameter is $\frac{1}{2}$ , are 


A) (-2,4)

B) (4,-1)

C) (-1,-4)

D) (-1,4)

Answer:

Option C

Explanation:

We know that parametric form y2=4ax is

 x= at2   and y=2at

 Here, y2  =-16x

$\therefore$      x= -4t2   and y= -8t

 Given,  t= $\frac{1}{2}$

 $\therefore$    $x=-4(\frac{1}{2})^{2}$ and  $ y=-8(\frac{1}{2})$

  x=-1 and y=-4

 Hence, cartesian coordinates are (-1,-4).