Question

Write the equation of a parabola whose directrix is

Answer 1

Answer:

y=0.5x²-4x-10.

Step-by-step explanation:

1) according to the definition of parabola:

d1=d2, then

$2) \ |y+1.5|=\sqrt{(x+4)^2+(y+2.5)^2} ;$

3) after evolution:

-(2y+4)=(x+4)²; ⇔

$y=-\frac{1}{2}x^2-4x-10.$