A drawing of a room has scale of 1/4 inch = 1 ft. what is the proportional relationship according to scale?
1 answer:
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Answer:
- 0 ≤ m ≤ 7
- 0.4541 cm/month; average rate of growth over last 4 months of study
Step-by-step explanation:
<u>Part A</u>:
The study was concluded after 7 months. The fish cannot be expected to maintain exponential growth for any significant period beyond the observation period. A reasonable domain is ...
0 ≤ m ≤ 7
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<u>Part B</u>:
The y-intercept is the value when m=0. It is the length of the fish at the start of the study.
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<u>Part C</u>:
The average rate of change on the interval [3, 7] is given by ...
(f(7) -f(3))/(7 -3) = (4(1.08^7) -4(1.08^3))/4 = 1.08^3·(1.08^4 -1)
≈ 0.4541 cm/month
This is the average growth rate of the fish in cm per month over the period from 3 months to 7 months.
If your directrix is a "y=" line, that means that the parabola opens either upwards or downwards (as opposed to the left or the right). Because it is in the character of a parabola to "hug" the focus, our parabola opens upwards. The vertex of a parabola sits exactly halfway between the directrix and the focus. Since our directrix is at y = -2 and the focus is at (1, 6) AND the parabola opens upward, the vertex is going to sit on the main transversal, which is also the "line" the focus sits on. The focus is on the line x = 1, so the vertex will also have that x coordinate. Halfway between the y points of the directrix and the focus, -2 and 6, respectively, is the y value of 2. So the vertex sits at (1, 2). The formula for this type of parabola is where h and k are the coordinates of the vertex and p is the DISTANCE that the focus is from the vertex. Our focus is 4 units from the vertex, so p = 4. Filling in our h, k, and p:
. Simplifying a bit gives us
. We can begin to isolate the y by dividing both sides by 16 to get
. Then we can add 2 to both sides to get the final equation
, choice 4 from above.