Limit Infinity 22E2Fd
1. **State the problem:** Evaluate the limit
$$\lim_{x \to \infty} \left( \frac{x^3}{3} \cdot 40 \cdot \frac{\pi}{4} - \arctan(x) + \frac{1}{3} \left( \frac{x^2}{2} + 0.5 \log(1 + x^2) \right) \right)$$
2. **Rewrite the expression for clarity:**
$$\lim_{x \to \infty} \left( \frac{40 \pi}{12} x^3 - \arctan(x) + \frac{1}{3} \left( \frac{x^2}{2} + \frac{1}{2} \log(1 + x^2) \right) \right)$$
3. **Simplify constants:**
$$\frac{40 \pi}{12} = \frac{10 \pi}{3}$$
So the expression becomes:
$$\lim_{x \to \infty} \left( \frac{10 \pi}{3} x^3 - \arctan(x) + \frac{1}{3} \left( \frac{x^2}{2} + \frac{1}{2} \log(1 + x^2) \right) \right)$$
4. **Analyze each term as $x \to \infty$:**
- $\frac{10 \pi}{3} x^3$ grows without bound to $+\infty$.
- $\arctan(x) \to \frac{\pi}{2}$ (finite constant).
- $\frac{1}{3} \left( \frac{x^2}{2} + \frac{1}{2} \log(1 + x^2) \right)$ grows without bound, dominated by $\frac{x^2}{6}$ term.
5. **Dominant term:** The cubic term $\frac{10 \pi}{3} x^3$ dominates the growth.
6. **Conclusion:** Since the leading term tends to $+\infty$, the whole expression tends to $+\infty$.
**Final answer:**
$$\lim_{x \to \infty} \left( \frac{x^3}{3} \cdot 40 \cdot \frac{\pi}{4} - \arctan(x) + \frac{1}{3} \left( \frac{x^2}{2} + 0.5 \log(1 + x^2) \right) \right) = +\infty$$