Answer:
y = -1/10x^2 +2.5
Step-by-step explanation:
The distance from focus to directrix is twice the distance from focus to vertex. The focus-directrix distance is the difference in y-values:
-1 -4 = -5
So, the distance from focus to vertex is p = -5/2 = -2.5. This places the focus 2.5 units below the vertex. Then the vertex is at (h, k) = (0, -1) +(0, 2.5) = (0, 1.5).
The scale factor of the parabola is 1/(4p) = 1/(4(-2.5)) = -1/10. Then the equation of the parabola is ...
y = (1/(4p))(x -h) +k
y = -1/10x^2 +2.5
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You can check the graph by making sure the focus and directrix are the same distance from the parabola everywhere. Of course, if the vertex is halfway between focus and directrix, the distances are the same there. Another point that is usually easy to check is the point on the parabola that is even with the focus. It should be as far from the focus as it is from the directrix. In this parabola, the focus is 5 units from the directrix, and we see the points on the parabola at y=-1 are 5 units from the focus.
Answer:
1002
Step-by-step explanation:
171x6=1026
171×2=342
1026-342=684
684+318=1002
Answer:
6 13/28
Step-by-step explanation:
Hope this helps!
Answer:
A. $2.26
Step-by-step explanation:
An equation for Harper's balance can be written similar to the one written for Raymond's balance. It will be ...
H(t) = 110(1.035)^t
For t = 2, the two balances will be ...
H(2) = 110(1.035^2) = 117.83
R(2) = 110(1.025^2) = 115.57
The difference is ...
$117.83 -115.57 = $2.26
Harper's account will have $2.26 more.
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As a quick estimate or sanity check, you can see that Harper's interest rate is 1% more than Raymond's. So, in 2 years, he will earn a little more than 2% more on his investment than Raymond earns. 2% of $110 is $2.20, so the difference can be expected to be slightly more than this.