Calculus for Economics
Math 140
Quiz 3
January 23, 2015
Dr. Pendergrass
On my honor, I have neither given nor received any aid on this work, nor am I aware
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Show your work; answers not supported by work will receive no credit. Each problem is worth 10 points.
1. Consider the function g(x) =
x2 + 5
.
x+2
(a) Find the domain of g.
(b) Find g(x − 1).
2. Consider the function f (x) = 2x − 1.
(a) Sketch the graph of f on the axes below.
y
4
2
−3
−2
−1
1
−2
−4
(b) Find the x-intercept of the graph.
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2
3
x
Math 140
Quiz 3
Dr. Pendergrass
3. In a certain business, the unit price when x units are demanded is p = −0.02x + 29. The total cost
when x units are manufactured is C(x) = 1.43x2 + 18.3x + 15.6.
(a) Find the revenue function R(x).
(b) Find the profit function P (x).
4. The profit function for a certain commodity is P (x) = −2.5(x2 − 19x + 34), where x is the level
of production (in units of thousands). What level of production x results in the maximum profit?
What is that maximum profit?
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