Math Problem Statement

Evaluate the integral \( \int \frac{8x + 4}{\sqrt{4x - 3}} \, dx \)

Solution

The integral you've provided is:

8x+44x3dx\int \frac{8x + 4}{\sqrt{4x - 3}} \, dx

To solve this, let's break it down step by step.

Step 1: Simplify the Integrand

Notice that the numerator can be split into two parts:

8x+44x3dx=8x4x3dx+44x3dx\int \frac{8x + 4}{\sqrt{4x - 3}} \, dx = \int \frac{8x}{\sqrt{4x - 3}} \, dx + \int \frac{4}{\sqrt{4x - 3}} \, dx

Step 2: Solve Each Integral Separately

Integral 1: 8x4x3dx\int \frac{8x}{\sqrt{4x - 3}} \, dx

Let u=4x3u = 4x - 3, then du=4dxdu = 4 \, dx, and dx=du4dx = \frac{du}{4}. Also, x=u+34x = \frac{u + 3}{4}.

Substituting these into the integral:

8x4x3dx=8u+34udu4=2u+3udu\int \frac{8x}{\sqrt{4x - 3}} \, dx = \int \frac{8 \cdot \frac{u + 3}{4}}{\sqrt{u}} \cdot \frac{du}{4} = 2 \int \frac{u + 3}{\sqrt{u}} \, du

This can be further simplified:

=2(uu+3u)du=2(u1/2+3u1/2)du= 2 \int \left( \frac{u}{\sqrt{u}} + \frac{3}{\sqrt{u}} \right) du = 2 \int \left( u^{1/2} + 3u^{-1/2} \right) du

Now, integrate term by term:

=2(23u3/2+6u1/2)=43u3/2+12u1/2= 2 \left( \frac{2}{3} u^{3/2} + 6u^{1/2} \right) = \frac{4}{3} u^{3/2} + 12u^{1/2}

Substitute back u=4x3u = 4x - 3:

=43(4x3)3/2+12(4x3)1/2= \frac{4}{3} (4x - 3)^{3/2} + 12(4x - 3)^{1/2}

Integral 2: 44x3dx\int \frac{4}{\sqrt{4x - 3}} \, dx

Using the same substitution u=4x3u = 4x - 3 and dx=du4dx = \frac{du}{4}:

44x3dx=4udu4=u1/2du\int \frac{4}{\sqrt{4x - 3}} \, dx = \int \frac{4}{\sqrt{u}} \cdot \frac{du}{4} = \int u^{-1/2} \, du

The integral of u1/2u^{-1/2} is:

2u1/2=24x32u^{1/2} = 2\sqrt{4x - 3}

Step 3: Combine the Results

Adding the results of both integrals:

43(4x3)3/2+12(4x3)1/2+24x3+C\frac{4}{3} (4x - 3)^{3/2} + 12(4x - 3)^{1/2} + 2\sqrt{4x - 3} + C

Simplifying:

8x+44x3dx=43(4x3)3/2+144x3+C\int \frac{8x + 4}{\sqrt{4x - 3}} \, dx = \frac{4}{3} (4x - 3)^{3/2} + 14\sqrt{4x - 3} + C

Where CC is the constant of integration.

Would you like more details on any step or have any questions?

Related Questions:

  1. How would the integration change if the numerator was 8x+28x + 2 instead of 8x+48x + 4?
  2. What technique could be used if the integrand was 8x+44x23\frac{8x + 4}{\sqrt{4x^2 - 3}} instead?
  3. How does the choice of substitution simplify the process in solving integrals?
  4. What is the significance of the constant of integration CC in indefinite integrals?
  5. How would this integral be approached using a numerical method like Simpson's Rule?

Tip:

When faced with complex integrals, look for algebraic simplifications or substitutions that can reduce the problem to a more standard form.

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Math Problem Analysis

Mathematical Concepts

Integration
Substitution
Algebraic Simplification

Formulas

Integral of the form \( \int \frac{f(x)}{\sqrt{g(x)}} \, dx \)
Substitution method

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Undergraduate