Levon, who weights 153 lb, sits 6 ft from the seesaw support. Find the constant of variation.
1 answer:
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Answer:
A: f(x)=10cos(2π/5 x)+10
Step-by-step explanation:
The coefficient of x in the cosine argument of the function will be 2π/period. Since the period is 5, the coefficient is 2π/5. This observation eliminates choices B and C.
The description "not a reflection of the parent function over the x-axis" means the multiplier of the cosine function is not negative, eliminating choice D.
The remaining choice A matches the description.
a) You are told the function is quadratic, so you can write cost (c) in terms of speed (s) as
... c = k·s² + m·s + n
Filling in the given values gives three equations in k, m, and n.
Subtracting each equation from the one after gives
Subtracting the first of these equations from the second gives
Using the next previous equation, we can find m.
Then from the first equation
[tex]28=100\cdot 0.01+10\cdot (-1)+n\\\\n=37[tex]
There are a variety of other ways the equation can be found or the system of equations solved. Any way you do it, you should end with
... c = 0.01s² - s + 37
b) At 150 kph, the cost is predicted to be
... c = 0.01·150² -150 +37 = 112 . . . cents/km
c) The graph shows you need to maintain speed between 40 and 60 kph to keep cost at or below 13 cents/km.
d) The graph has a minimum at 12 cents per km. This model predicts it is not possible to spend only 10 cents per km.
