Levi and his family belong to a family share plan for their cell phones. The pan includes unlimited minutes, text, and
1 answer:
Actually Welcome to the concept of calculations of bills.
The bill calculation goes as equation,
y = $250 + n*($10)
here, n = number of lines,
1.) For n = 2 , Y = cost = 250 + 20 = $270
2.) for n = 4 , Y = $290
3.) for n = 6 , Y = $310
4.) for n = x, Y = $250 + x*($10)
for lastly 12 members we get as,
Y = 250 + (12)*(10) = 250+120 = $370
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Answer:
a) h = 123/x^2
b) S = x^2 +492/x
c) x ≈ 6.27
d) S'' = 6; area is a minimum (Y)
e) Amin ≈ 117.78 m²
Step-by-step explanation:
a) The volume is given by ...
V = Bh
where B is the area of the base, x^2, and h is the height. Filling in the given volume, and solving for the height, we get:
123 = x^2·h
h = 123/x^2
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b) The surface area is the sum of the area of the base (x^2) and the lateral area, which is the product of the height and the perimeter of the base.
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c) The derivative of the area with respect to x is ...
When this is zero, area is at an extreme.
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d) The second derivative is ...
This is positive, so the value of x found represents a minimum of the area function.
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e) The minimum area is ...
The minimum area of metal used is about 117.78 m².