1. **Problem Statement:**
Find the increase in the voting population $N(t)$ during the next 3 years given the rate of change $$\frac{dN}{dt} = \frac{100t}{(1+t)^2}$$ and initial population $N(0)$.
2. **Formula and Explanation:**
The increase in population from $t=0$ to $t=3$ is given by the definite integral of the rate of change:
$$\Delta N = \int_0^3 \frac{100t}{(1+t)^2} dt$$
3. **Integration Steps:**
Rewrite the integral:
$$\int_0^3 \frac{100t}{(1+t)^2} dt = 100 \int_0^3 \frac{t}{(1+t)^2} dt$$
Let $u = 1 + t$, then $du = dt$ and when $t=0$, $u=1$; when $t=3$, $u=4$.
Rewrite $t = u - 1$:
$$100 \int_1^4 \frac{u - 1}{u^2} du = 100 \int_1^4 \left(\frac{u}{u^2} - \frac{1}{u^2}\right) du = 100 \int_1^4 \left(\frac{1}{u} - u^{-2}\right) du$$
4. **Integrate term-by-term:**
$$100 \left[ \int_1^4 \frac{1}{u} du - \int_1^4 u^{-2} du \right] = 100 \left[ \ln|u| \Big|_1^4 - \left(-\frac{1}{u}\right) \Big|_1^4 \right]$$
5. **Evaluate definite integrals:**
$$= 100 \left[ \ln 4 - \ln 1 + \left(\frac{1}{1} - \frac{1}{4}\right) \right] = 100 \left[ \ln 4 + \frac{3}{4} \right]$$
6. **Final answer:**
The increase in population over 3 years is:
$$\boxed{100 \left( \ln 4 + \frac{3}{4} \right) \text{ thousands}}$$
This means the population increases by approximately $100 \times (1.3863 + 0.75) = 213.63$ thousands in 3 years.
Population Increase Bb4B84
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