1. The problem is to identify two correct statements about the differential equation $$\frac{dX}{dt} + e^{2t} \cdot X = t^2$$.
2. First, identify the dependent and independent variables. In this equation, $X$ depends on $t$, so $X$ is the dependent variable and $t$ is the independent variable. This confirms statement A is correct and B is incorrect.
3. To solve the linear first-order differential equation, use the integrating factor method. The standard form is:
$$\frac{dX}{dt} + P(t)X = Q(t)$$
where here $P(t) = e^{2t}$ and $Q(t) = t^2$.
4. The integrating factor $\mu(t)$ is:
$$\mu(t) = e^{\int P(t) dt} = e^{\int e^{2t} dt}$$
Calculate the integral:
$$\int e^{2t} dt = \frac{1}{2} e^{2t} + C$$
Ignoring the constant, the integrating factor is:
$$\mu(t) = e^{\frac{1}{2} e^{2t}}$$
5. Multiply both sides of the differential equation by $\mu(t)$:
$$e^{\frac{1}{2} e^{2t}} \frac{dX}{dt} + e^{\frac{1}{2} e^{2t}} e^{2t} X = t^2 e^{\frac{1}{2} e^{2t}}$$
6. The left side is the derivative of $X \cdot \mu(t)$:
$$\frac{d}{dt} \left(X e^{\frac{1}{2} e^{2t}}\right) = t^2 e^{\frac{1}{2} e^{2t}}$$
7. Integrate both sides:
$$X e^{\frac{1}{2} e^{2t}} = \int t^2 e^{\frac{1}{2} e^{2t}} dt + C$$
8. Solve for $X(t)$:
$$X(t) = e^{-\frac{1}{2} e^{2t}} \int t^2 e^{\frac{1}{2} e^{2t}} dt + Ce^{-\frac{1}{2} e^{2t}}$$
9. Comparing with the options, statement D matches this solution form exactly.
10. Therefore, the two correct statements are A and D.
Final answer: A and D are correct.
Diff Eq Variables 55Af7A
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