Because the focus is (-2,-2) and the directrix is y = -4, the vertex is (-2,-3).
Consider an arbitrary point (x,y) on the parabola.
The square of the distance between the focus and P is
(y+2)² + (x+2)²
The square of the distance from the point to the directrix is
(y+4)²
Therefore
(y+4)² = (y+2)² + (x+2)²
y² + 8y + 16 = y² + 4y + 4 + (x+2)²
4y = (x+2)² - 12
y = (1/4)(x+2)² - 3
Answer:
Answer:
Step-by-step explanation:
(3,0),(4,1) ⇒ (x₁,y₁),(x₂,y₂)
to find the equation of the line
y-y₁= {(y₂-y₁)/(x₂-x₁)}(x-x₁)
y-0= [(1-0)/(4-3)] (x-3)
y-0 = 1/1(x-3)
y-0 = x-3
y= x-3+0
y=x-3
compare to y=mx+c, where m is the gradient and c is the intercept on y-axis
m=1, c=-3
∴the y-intercept of the line is -3
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