The general form of a parabola when using the focus and directrix is:
(x - h)² = 4p(y - k) where (h, k) is the vertex of the parabola and 'p' is distance between vertex and the focus. We use this form due to the fact we can see the parabola will open up based on the directrix being below the focus. Remember that the parabola will hug the focus and run away from the directrix. The formula would be slightly different if the parabola was opening either left or right.
Given a focus of (-2,4) and a directrix of y = 0, we can assume the vertex of the parabola is exactly half way in between the focus and the directrix. The focus and vertex with be stacked one above the other, therefore the vertex will be (-2, 2) and the value of 'p' will be 2. We can now write the equation of the parabola:
(x + 2)² = 4(2)(y - 2)
(x + 2)² = 8(y - 2) Now you can solve this equation for y if you prefer solving for 'y' in terms of 'x'
Answer:216
Step-by-step explanation:
Answer:
length of segment AB is 13
OR
AB = 13
Step-by-step explanation:
Use the Pythagorean Theorem with c being the length of segment AB.
a^2 + b^2 = c^2
5^2 + 12^2 = c^2
169 = c ^2 (square root both sides to get c by itself)
13 = c
Answer: The midpoint of segment PQ is the number 2.5
note: 2.5 as a fraction is 5/2; as a mixed number 2.5 converts to 2&1/2
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Explanation:
Apply the midpoint formula to get the midpoint of -8 and 6
We simply add up the values and divide by 2 and we get (-8+6)/2 = -2/2 = -1
So point Q is at -1 on the number line, which is exactly halfway from R to P
Focus on just points P and Q now. Apply the midpoint formula again
Q = -1
P = 6
(Q+P)/2 = (-1+6)/2 = 5/2 = 2.5
So the midpoint of segment PQ is 2.5
The decimal 2.5 can be written as the mixed number 2&1/2, showing that this new point is exactly halfway between 2 and 3.
