Cost Revenue
1.2 Problem Statement: Given the total cost function $TC = 200 + 3Q$ and the demand function $P = 107 - 2Q$.
1. Write down the total revenue function.
2. Graph the total cost and total revenue functions on the same axes.
3. Estimate the break-even points both graphically and algebraically.
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1. Total revenue (TR) is price times quantity:
$$TR = P \times Q = (107 - 2Q)Q = 107Q - 2Q^2$$
2. To find break-even points, set total revenue equal to total cost:
$$TR = TC$$
$$107Q - 2Q^2 = 200 + 3Q$$
Rearrange:
$$-2Q^2 + 107Q - 3Q - 200 = 0$$
$$-2Q^2 + 104Q - 200 = 0$$
Multiply both sides by $-1$ to simplify:
$$2Q^2 - 104Q + 200 = 0$$
Divide entire equation by 2:
$$Q^2 - 52Q + 100 = 0$$
3. Solve quadratic equation using the quadratic formula:
$$Q = \frac{52 \pm \sqrt{52^2 - 4 \times 1 \times 100}}{2}$$
Calculate discriminant:
$$52^2 = 2704$$
$$4 \times 1 \times 100 = 400$$
$$\sqrt{2704 - 400} = \sqrt{2304} = 48$$
So,
$$Q = \frac{52 \pm 48}{2}$$
Two solutions:
$$Q_1 = \frac{52 + 48}{2} = \frac{100}{2} = 50$$
$$Q_2 = \frac{52 - 48}{2} = \frac{4}{2} = 2$$
4. Break-even points are at $Q=2$ and $Q=50$.
Calculate corresponding prices:
At $Q=2$:
$$P = 107 - 2(2) = 107 - 4 = 103$$
At $Q=50$:
$$P = 107 - 2(50) = 107 - 100 = 7$$
5. Graphically, the total cost line $TC = 200 + 3Q$ is a straight line starting at 200 when $Q=0$ with slope 3.
The total revenue curve $TR = 107Q - 2Q^2$ is a downward-opening parabola.
The break-even points are where these two graphs intersect at $Q=2$ and $Q=50$.
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Final answers:
- Total revenue function: $TR = 107Q - 2Q^2$
- Break-even points: $Q=2$ and $Q=50$ with prices $P=103$ and $P=7$ respectively.