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13. The profit, in thousands of dollars, from the sale of x kilogram of coffee bean can be modelled by the function () = 5−400 +600 . a) State the asymptotes and the intercepts. Then, sketch a graph of this function using its key features. (5 pts) b) State the domain and range in this context. (2 points) c) Explain the significance of the horizontal asymptote. (1 point) d) Algebraically, find how much amount of tuna fish, in kg, should be sold to have a profit of exactly $4000? (4 points) SOLUTION

User Vadiklk
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Answer: a) The profit function can be written as:

P(x) = 5x - 400x + 600

To find the asymptotes, we can look at the denominator of the second term, which is (x - 3). This means that there is a vertical asymptote at x = 3. To find the intercepts, we can set P(x) = 0:

5x - 400x + 600 = 0

Solving for x, we get:

x = 1.5 and x = 2.5

Therefore, there are x-intercepts at (1.5, 0) and (2.5, 0). To sketch the graph, we can also note that the coefficient of x^2 is negative, which means that the graph is a downward-facing parabola.

b) The domain of the function is the set of all possible values of x, which in this context represents the amount of coffee sold. Since we cannot sell a negative amount of coffee, the domain is x ≥ 0.

The range of the function is the set of all possible values of P(x), which represents the profit. Since the coefficient of x^2 is negative, the maximum profit occurs at the vertex of the parabola. The vertex has x-coordinate:

x = -b/(2a) = -(-400)/(2(-200)) = 1

Therefore, the maximum profit occurs when x = 1. The vertex has y-coordinate:

P(1) = 5(1) - 400(1) + 600 = 205

Since the coefficient of x^2 is negative, the range is (-∞, 205].

c) The horizontal asymptote of the function is y = -400, which represents the long-term average profit per kilogram of coffee sold. This means that as x gets very large, the profit per kilogram approaches -400. This could happen, for example, if the cost of producing the coffee increased significantly while the price remained the same.

d) To find the amount of coffee that must be sold to make a profit of $4000, we can set P(x) = 4000 and solve for x:

5x - 400x + 600 = 4000

Simplifying, we get:

-395x = -3400

Dividing both sides by -395, we get:

x ≈ 8.61

Therefore, approximately 8.61 kg of coffee must be sold to make a profit of $4000.

Explanation:

User Abdul Fatir
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