1. **State the problem:** Find the length of the curve given by the vector function $$\mathbf{r}(t) = \langle t^2, 2t, \ln t \rangle$$ for $$1 \leq t \leq e$$.
2. **Formula for curve length:** The length $$L$$ of a curve defined by $$\mathbf{r}(t)$$ from $$t=a$$ to $$t=b$$ is given by:
$$
L = \int_a^b \| \mathbf{r}'(t) \| \, dt
$$
where $$\mathbf{r}'(t)$$ is the derivative of $$\mathbf{r}(t)$$ and $$\| \mathbf{r}'(t) \|$$ is its magnitude.
3. **Find the derivative:**
$$
\mathbf{r}'(t) = \left\langle \frac{d}{dt} t^2, \frac{d}{dt} 2t, \frac{d}{dt} \ln t \right\rangle = \langle 2t, 2, \frac{1}{t} \rangle
$$
4. **Find the magnitude:**
$$
\| \mathbf{r}'(t) \| = \sqrt{(2t)^2 + 2^2 + \left(\frac{1}{t}\right)^2} = \sqrt{4t^2 + 4 + \frac{1}{t^2}}
$$
5. **Simplify the expression under the square root:**
$$
\sqrt{4t^2 + 4 + \frac{1}{t^2}} = \sqrt{\frac{4t^4 + 4t^2 + 1}{t^2}} = \frac{\sqrt{4t^4 + 4t^2 + 1}}{t}
$$
6. **Recognize the perfect square:**
$$
4t^4 + 4t^2 + 1 = (2t^2 + 1)^2
$$
7. **Substitute back:**
$$
\| \mathbf{r}'(t) \| = \frac{2t^2 + 1}{t}
$$
8. **Set up the integral for length:**
$$
L = \int_1^e \frac{2t^2 + 1}{t} \, dt = \int_1^e \left(2t + \frac{1}{t}\right) dt
$$
9. **Integrate term-by-term:**
$$
\int_1^e 2t \, dt = \left[t^2\right]_1^e = e^2 - 1
$$
$$
\int_1^e \frac{1}{t} \, dt = \left[\ln t\right]_1^e = \ln e - \ln 1 = 1 - 0 = 1
$$
10. **Add the results:**
$$
L = (e^2 - 1) + 1 = e^2
$$
**Final answer:** The length of the curve is $$\boxed{e^2}$$.
Curve Length 430Cc5
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