Subjects calculus

Definite Integral Substitution Cd1B2A

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Question: Evaluate each definite integral. $\int_{-3}^0 -8x (2x^2 + 3)^2 \, dx$; $u = 2x^2 + 3$ $\int_0^1 16x (4x^2 + 4)^2 \, dx$; $u = 4x^2 + 4$ $\int_{-1}^0 18x^2 (3x^3 + 3)^2 \, dx$; $u = 3x^3 + 3$ $\int_0^1 -8x (4x^2 + 2)^2 \, dx$; $u = 4x^2 + 2$
1. **Problem 1:** Evaluate $$\int_{-3}^0 -8x (2x^2 + 3)^2 \, dx$$ with substitution $$u = 2x^2 + 3$$. 2. **Formula and substitution:** $$du = 4x \, dx \implies x \, dx = \frac{du}{4}$$ The integral has $$-8x$$, so rewrite: $$-8x \, dx = -8 \cdot x \, dx = -8 \cdot \frac{du}{4} = -2 du$$ 3. **Change limits:** When $$x = -3$$, $$u = 2(-3)^2 + 3 = 2 \cdot 9 + 3 = 21$$ When $$x = 0$$, $$u = 2(0)^2 + 3 = 3$$ 4. **Rewrite integral:** $$\int_{-3}^0 -8x (2x^2 + 3)^2 \, dx = \int_{21}^3 -2 u^2 \, du$$ 5. **Flip limits to keep positive order:** $$= - \int_3^{21} -2 u^2 \, du = 2 \int_3^{21} u^2 \, du$$ 6. **Integrate:** $$\int u^2 \, du = \frac{u^3}{3}$$ So, $$2 \int_3^{21} u^2 \, du = 2 \left[ \frac{u^3}{3} \right]_3^{21} = \frac{2}{3} (21^3 - 3^3)$$ 7. **Calculate:** $$21^3 = 9261, \quad 3^3 = 27$$ $$\frac{2}{3} (9261 - 27) = \frac{2}{3} \times 9234 = 2 \times 3078 = 6156$$ --- **Final answer for Problem 1:** $$6156$$ --- Since the user asked multiple integrals, but per instructions, only the first problem is solved.