Math Problem Statement

∫ dx / (x^(3/2) - √x)

Solution

The integral provided is:

dxx3/2x\int \frac{dx}{x^{3/2} - \sqrt{x}}

Let me help you solve this step by step.

Step 1: Simplify the powers of xx

Recall that:

  • x3/2x^{3/2} is x1.5x^{1.5},
  • x=x1/2\sqrt{x} = x^{1/2}.

Thus, the integral becomes:

dxx3/2x1/2.\int \frac{dx}{x^{3/2} - x^{1/2}}.

Step 2: Factor the denominator

Factor x1/2x^{1/2} from the denominator:

x1/2(x11)=x1/2(x1).x^{1/2}(x^{1} - 1) = x^{1/2}(x - 1).

Thus, the integral becomes:

dxx1/2(x1).\int \frac{dx}{x^{1/2}(x - 1)}.

Step 3: Substitution

Let u=x=x1/2u = \sqrt{x} = x^{1/2}, so du=12xdxdu = \frac{1}{2\sqrt{x}}dx, or dx=2ududx = 2u \, du.

Substitute into the integral:

2uduu(u21).\int \frac{2u \, du}{u (u^2 - 1)}.

The uu's cancel out, leaving:

2duu21.2 \int \frac{du}{u^2 - 1}.

Step 4: Recognize a standard integral

The integral duu21\int \frac{du}{u^2 - 1} is a standard result and can be solved using partial fractions.

1u21=12(1u11u+1).\frac{1}{u^2 - 1} = \frac{1}{2} \left( \frac{1}{u - 1} - \frac{1}{u + 1} \right).

Thus, the integral becomes:

2duu21=(1u11u+1)du.2 \int \frac{du}{u^2 - 1} = \int \left( \frac{1}{u - 1} - \frac{1}{u + 1} \right) du.

Step 5: Solve the integral

This is straightforward to integrate:

(1u11u+1)du=lnu1lnu+1+C.\int \left( \frac{1}{u - 1} - \frac{1}{u + 1} \right) du = \ln |u - 1| - \ln |u + 1| + C.

This simplifies to:

lnu1u+1+C.\ln \left| \frac{u - 1}{u + 1} \right| + C.

Step 6: Substitute back u=xu = \sqrt{x}

Finally, substitute back u=xu = \sqrt{x} to get the final answer:

lnx1x+1+C.\ln \left| \frac{\sqrt{x} - 1}{\sqrt{x} + 1} \right| + C.

Thus, the solution to the integral is:

lnx1x+1+C.\ln \left| \frac{\sqrt{x} - 1}{\sqrt{x} + 1} \right| + C.


Would you like any further explanation or details on a specific step?

5 Related Questions:

  1. How can you solve other integrals involving square roots?
  2. What are some common techniques for simplifying integrals using substitution?
  3. How does partial fraction decomposition help in solving integrals?
  4. Can you explain how to handle improper integrals?
  5. What are some alternative methods for factoring the denominator of integrals?

Tip:

When encountering powers or square roots in integrals, substitution methods like u=xu = \sqrt{x} often simplify the process dramatically!

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Math Problem Analysis

Mathematical Concepts

Calculus
Integration
Substitution Method
Partial Fractions

Formulas

Substitution: u = √x
Partial Fraction Decomposition
Standard Integral: ∫ du / (u^2 - 1)

Theorems

Substitution Theorem
Partial Fraction Decomposition Theorem

Suitable Grade Level

Grades 11-12, College Calculus