Math Problem Statement

Evaluate the definite integral (6x^2+8)/(sqrt(x))dx from 2 to 8

Solution

To evaluate the definite integral:

286x2+8xdx\int_{2}^{8} \frac{6x^2 + 8}{\sqrt{x}} \, dx

Step 1: Simplify the integrand

Split the numerator as:

6x2+8x=6x2x+8x=6x3/2+8x1/2\frac{6x^2 + 8}{\sqrt{x}} = \frac{6x^2}{\sqrt{x}} + \frac{8}{\sqrt{x}} = 6x^{3/2} + 8x^{-1/2}

Step 2: Write the integral in terms of these simplified expressions

The integral becomes:

28(6x3/2+8x1/2)dx\int_{2}^{8} \left( 6x^{3/2} + 8x^{-1/2} \right) \, dx

Step 3: Integrate term by term

Use the power rule for integration, which states:

xndx=xn+1n+1,n1\int x^n \, dx = \frac{x^{n+1}}{n+1}, \quad n \neq -1

First term:

6x3/2dx=6x5/25/2=125x5/2\int 6x^{3/2} \, dx = 6 \cdot \frac{x^{5/2}}{5/2} = \frac{12}{5} x^{5/2}

Second term:

8x1/2dx=8x1/21/2=16x1/2\int 8x^{-1/2} \, dx = 8 \cdot \frac{x^{1/2}}{1/2} = 16x^{1/2}

Thus, the antiderivative is:

125x5/2+16x1/2\frac{12}{5} x^{5/2} + 16x^{1/2}

Step 4: Apply the limits of integration

Evaluate the definite integral from x=2x = 2 to x=8x = 8:

[125x5/2+16x1/2]28\left[ \frac{12}{5} x^{5/2} + 16x^{1/2} \right]_2^8

Evaluate at x=8x = 8:

125(85/2)+16(81/2)=125(648)+168\frac{12}{5} (8^{5/2}) + 16 (8^{1/2}) = \frac{12}{5} \cdot (64 \sqrt{8}) + 16 \cdot \sqrt{8}

Evaluate at x=2x = 2:

125(25/2)+16(21/2)=125(42)+162\frac{12}{5} (2^{5/2}) + 16 (2^{1/2}) = \frac{12}{5} \cdot (4 \sqrt{2}) + 16 \cdot \sqrt{2}

Step 5: Subtract the results

The definite integral is:

[ \left[ \frac{12}{5} (64 \sqrt{8}) + 16 \sqrt{8} \right] - \left[ \frac{12}{5} (4 \sqrt{2}) + 16 \sqrt{2} \right] ]

If you’d like, I can proceed with a numerical approximation of this expression or leave it in symbolic form. Let me know!


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Math Problem Analysis

Mathematical Concepts

Integration
Definite Integrals
Simplifying Algebraic Expressions

Formulas

Power Rule for Integration: ∫x^n dx = x^(n+1)/(n+1) for n ≠ -1
Properties of Definite Integrals: F(b) - F(a)

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12