1. **Problem Statement:** We are given a profit function for a production division:
$$P(x) = \frac{500 \ln(x + 1)}{(x + 1)^2}$$
where $x$ is in hundreds of units and $P(x)$ is in thousands of dollars. We need to find the average profit over the interval from $x=0$ to $x=10$ hundred units using integral calculus.
2. **Formula for Average Value of a Function:**
The average value $\bar{P}$ of a continuous function $P(x)$ over the interval $[a,b]$ is given by:
$$\bar{P} = \frac{1}{b - a} \int_a^b P(x) \, dx$$
Here, $a=0$ and $b=10$.
3. **Set up the integral:**
$$\bar{P} = \frac{1}{10 - 0} \int_0^{10} \frac{500 \ln(x + 1)}{(x + 1)^2} \, dx = \frac{1}{10} \int_0^{10} \frac{500 \ln(x + 1)}{(x + 1)^2} \, dx$$
4. **Simplify the constant factor:**
$$\bar{P} = 50 \int_0^{10} \frac{\ln(x + 1)}{(x + 1)^2} \, dx$$
5. **Substitution:** Let $t = x + 1$, so when $x=0$, $t=1$ and when $x=10$, $t=11$. Also, $dx = dt$.
The integral becomes:
$$\int_1^{11} \frac{\ln t}{t^2} \, dt$$
6. **Integration by parts:**
Let:
- $u = \ln t \implies du = \frac{1}{t} dt$
- $dv = t^{-2} dt \implies v = -t^{-1}$
Then:
$$\int \frac{\ln t}{t^2} dt = uv - \int v \, du = -\frac{\ln t}{t} - \int -\frac{1}{t} \cdot \frac{1}{t} dt = -\frac{\ln t}{t} + \int \frac{1}{t^2} dt$$
7. **Evaluate the remaining integral:**
$$\int \frac{1}{t^2} dt = \int t^{-2} dt = -t^{-1} + C = -\frac{1}{t} + C$$
8. **Combine results:**
$$\int \frac{\ln t}{t^2} dt = -\frac{\ln t}{t} - \frac{1}{t} + C = -\frac{\ln t + 1}{t} + C$$
9. **Evaluate definite integral from 1 to 11:**
$$\int_1^{11} \frac{\ln t}{t^2} dt = \left[-\frac{\ln t + 1}{t}\right]_1^{11} = \left(-\frac{\ln 11 + 1}{11}\right) - \left(-\frac{\ln 1 + 1}{1}\right)$$
Since $\ln 1 = 0$:
$$= -\frac{\ln 11 + 1}{11} + 1 = 1 - \frac{\ln 11 + 1}{11}$$
10. **Calculate the average profit:**
$$\bar{P} = 50 \times \left(1 - \frac{\ln 11 + 1}{11}\right) = 50 \left(1 - \frac{\ln 11 + 1}{11}\right)$$
This is the average profit in thousands of dollars over the interval from 0 to 10 hundred units.
**Final answer:**
$$\boxed{\bar{P} = 50 \left(1 - \frac{\ln 11 + 1}{11}\right) \text{ thousand dollars}}$$
This completes the solution.
Average Profit 6C7C21
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