Math Problem Statement

Evaluate the integral from -1 to 3 of (2x^2 - 3x + 4) dx.

Solution

To evaluate the integral

13(2x23x+4)dx,\int_{-1}^{3} (2x^2 - 3x + 4) \, dx,

we proceed by integrating each term separately and then applying the limits.

Step 1: Find the Antiderivative

  1. For 2x22x^2, the antiderivative is 2x33\frac{2x^3}{3}.
  2. For 3x-3x, the antiderivative is 3x22-\frac{3x^2}{2}.
  3. For 44, the antiderivative is 4x4x.

Thus, the antiderivative of 2x23x+42x^2 - 3x + 4 is:

2x333x22+4x.\frac{2x^3}{3} - \frac{3x^2}{2} + 4x.

Step 2: Apply the Limits

Now, we evaluate this expression from x=1x = -1 to x=3x = 3:

[2x333x22+4x]13.\left[\frac{2x^3}{3} - \frac{3x^2}{2} + 4x\right]_{-1}^{3}.

At x=3x = 3:

2(3)333(3)22+4(3)=2273392+12=1813.5+12=16.5.\frac{2(3)^3}{3} - \frac{3(3)^2}{2} + 4(3) = \frac{2 \cdot 27}{3} - \frac{3 \cdot 9}{2} + 12 = 18 - 13.5 + 12 = 16.5.

At x=1x = -1:

2(1)333(1)22+4(1)=2(1)33124=23324=296.\frac{2(-1)^3}{3} - \frac{3(-1)^2}{2} + 4(-1) = \frac{2 \cdot (-1)}{3} - \frac{3 \cdot 1}{2} - 4 = -\frac{2}{3} - \frac{3}{2} - 4 = -\frac{29}{6}.

Step 3: Compute the Difference

Now, subtract the value at x=1x = -1 from the value at x=3x = 3:

16.5(296)=16.5+296=99+296=1286=643.16.5 - \left(-\frac{29}{6}\right) = 16.5 + \frac{29}{6} = \frac{99 + 29}{6} = \frac{128}{6} = \frac{64}{3}.

Final Answer

13(2x23x+4)dx=643.\int_{-1}^{3} (2x^2 - 3x + 4) \, dx = \frac{64}{3}.

Would you like further details, or do you have any questions?


Here are some related questions to extend your understanding:

  1. How do you find the antiderivative of a polynomial with more terms?
  2. How can definite integrals be applied to compute the area under a curve?
  3. What methods can be used if the integrand was a trigonometric function instead?
  4. How would you set up an integral for a region bounded by two curves?
  5. How does the Fundamental Theorem of Calculus connect differentiation and integration?

Tip: When evaluating definite integrals, carefully simplify each step, especially when substituting values to avoid errors.

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Math Problem Analysis

Mathematical Concepts

Calculus
Definite Integral
Polynomial Integration

Formulas

∫ (ax^n) dx = (a/(n+1)) * x^(n+1) + C
Fundamental Theorem of Calculus: ∫[a, b] f(x) dx = F(b) - F(a)

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12