1. **Problem statement:** Evaluate the definite integral $$\int_1^2 (5x^6 + 2x - 1) \, dx$$ and the indefinite integral $$\int 5x^3 \, dx$$.
2. **Formula and rules:**
- For definite integrals, use the Fundamental Theorem of Calculus: $$\int_a^b f(x) \, dx = F(b) - F(a)$$ where $$F'(x) = f(x)$$.
- For indefinite integrals, use the power rule: $$\int x^n \, dx = \frac{x^{n+1}}{n+1} + C$$ for $$n \neq -1$$.
3. **Evaluate the definite integral:**
- Integrate term-by-term:
$$\int (5x^6 + 2x - 1) \, dx = 5 \int x^6 \, dx + 2 \int x \, dx - \int 1 \, dx$$
- Using the power rule:
$$5 \cdot \frac{x^{7}}{7} + 2 \cdot \frac{x^{2}}{2} - x + C = \frac{5}{7}x^{7} + x^{2} - x + C$$
- Apply limits from 1 to 2:
$$\left(\frac{5}{7} \cdot 2^{7} + 2^{2} - 2\right) - \left(\frac{5}{7} \cdot 1^{7} + 1^{2} - 1\right)$$
- Calculate values:
$$2^{7} = 128$$
So,
$$\left(\frac{5}{7} \cdot 128 + 4 - 2\right) - \left(\frac{5}{7} + 1 - 1\right) = \left(\frac{640}{7} + 2\right) - \frac{5}{7} = \frac{640}{7} + 2 - \frac{5}{7} = \frac{635}{7} + 2 = \frac{635}{7} + \frac{14}{7} = \frac{649}{7}$$
4. **Evaluate the indefinite integral:**
- $$\int 5x^{3} \, dx = 5 \int x^{3} \, dx = 5 \cdot \frac{x^{4}}{4} + C = \frac{5}{4} x^{4} + C$$
**Final answers:**
- $$\int_1^2 (5x^6 + 2x - 1) \, dx = \frac{649}{7}$$
- $$\int 5x^{3} \, dx = \frac{5}{4} x^{4} + C$$
Integral Evaluation E266F8
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