Answer:
-2, 8/3
Step-by-step explanation:
You can consider the area to be that of a trapezoid with parallel bases f(a) and f(4), and width (4-a). The area of that trapezoid is ...
A = (1/2)(f(a) +f(4))(4 -a)
= (1/2)((3a -1) +(3·4 -1))(4 -a)
= (1/2)(3a +10)(4 -a)
We want this area to be 12, so we can substitute that value for A and solve for "a".
12 = (1/2)(3a +10)(4 -a)
24 = (3a +10)(4 -a) = -3a² +2a +40
3a² -2a -16 = 0 . . . . . . subtract the right side
(3a -8)(a +2) = 0 . . . . . factor
Values of "a" that make these factors zero are ...
a = 8/3, a = -2
The values of "a" that make the area under the curve equal to 12 are -2 and 8/3.
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<em>Alternate solution</em>
The attachment shows a solution using the numerical integration function of a graphing calculator. The area under the curve of function f(x) on the interval [a, 4] is the integral of f(x) on that interval. Perhaps confusingly, we have called that area f(a). As we have seen above, the area is a quadratic function of "a". I find it convenient to use a calculator's functions to solve problems like this where possible.
Answer:
positive
Step-by-step explanation:
Answer:
35% chose baseball or soccer
Step-by-step explanation:
baseball or soccer = 20% + 15% = 35%
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The categories add to 100%, so are mutually exclusive, as you expect when they are "favorite sport" categories. Hence the union of two of them will be their sum. (Otherwise, you'd have to subtract the amount by which the categories overlap.)
Answer: 216
Step-by-step explanation:
Answer:
24 in³
Step-by-step explanation:
The volume of a prism is given by the formula ...
V = Bh
where B is the area of the base, and h is the height.
The volume of a pyramid is given by the formula ...
V = (1/3)Bh
where B and h have the same definitions.
For a pyramid with the same B and h as a prism, the volume is 1/3 that of the prism:
(1/3) × (72 in³) = 24 in³ . . . . volume of the pyramid