The directrix of a parabola is y=−4y=−4 . The focus of the parabola is (−2,−2)(−2,−2) .
1 answer:
Refer to the diagram shown below.
The directrix is y = -4 and the focus is (-2, -2).
Therefore the vertex is at (-2, -3).
Consider an arbitrary point (x,y) on the parabola.
The square of distance from the focus to the point is
(x+2)² + (y+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:
The directrix is y = -4 and the focus is (-2, -2).
Therefore the vertex is at (-2, -3).
Consider an arbitrary point (x,y) on the parabola.
The square of distance from the focus to the point is
(x+2)² + (y+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:
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Variable d represents the time per minute Lilianna spends in the park.
Step-by-step explanation:
Lilianna uses calories per minute just by sitting. She uses 1 more calorie per minute by walking.
Liliana uses a total of calories walking to the park.
Lilianna uses the equation, to represent the situation.
Here, variable d represents the time per minute she spends in the park.
and is given as,
It can be written as,
Solving for d,
Thus, she spend d= 7 minutes total to the park.