Solve Integration Problem: ∫x^3/(x^2+1)^(3/2) dx

In summary, the conversation discusses solving the equation ∫x^3/(x^2+1)^(3/2) dx using integration by parts. The expert provides a summary of the steps involved and the final solution.
  • #1
tmwong
24
0
can anyone solve this equation?

∫x^3/(x^2+1)^(3/2) dx
 
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  • #2
[tex]\int\frac{x^3}{\left(x^2+1\right)^{\frac{3}{2}}}dx=\frac{x^2+2}{\sqrt{x^2+1}}+C[/tex]
 
  • #3
Hmm, maybe integration by parts would work?
[tex]\frac{x^3}{\left(x^2+1\right)^{\frac{3}{2}}}=x^2\frac{x}{\left(x^2+1\right)^{\frac{3}{2}}}[/tex]
The primitive of the factor on the right is
[tex]\frac{-1}{\sqrt{x^2+1}}[/tex]
looks like it may lead somewhere.
Appears tedious though
 
Last edited:
  • #4
 
  • #5
NeutronStar said:
[tex]\int\frac{x^3}{\left(x^2+1\right)^{\frac{3}{2}}}dx=
\frac{x^2+2}{\sqrt{x^2+1}}+C[/tex]

Proof
[tex]\int\frac{x^3}{\left(x^2+1\right)^{\frac{3}{2}}}dx=
\int\frac{x^2}{2}\frac{2x}{(\sqrt{x^2+1})^3}dx=
-\frac{x^2}{\sqrt{x^2+1}}+\int\frac{2x}{\sqrt{x^2+1}}dx=
-\frac{x^2}{\sqrt{x^2+1}}+2\sqrt{x^2+1}+C=
\frac{x^2+2}{\sqrt{x^2+1}}+C[/tex]
 

Related to Solve Integration Problem: ∫x^3/(x^2+1)^(3/2) dx

1. What is integration?

Integration is a mathematical process of finding the area under a curve. It involves finding the antiderivative of a function and calculating the area under the curve between two given points.

2. What is the formula for integration?

The formula for integration is ∫ f(x) dx = F(x) + C, where f(x) is the function being integrated and F(x) is its antiderivative. The constant C is known as the constant of integration.

3. What is the given integration problem asking for?

The given integration problem is asking for the antiderivative of the function f(x) = x^3/(x^2+1)^(3/2) with respect to x.

4. How do you solve this integration problem?

To solve this integration problem, we can use the substitution method. Let u = x^2+1, then du/dx = 2x and dx = du/2x. Substituting into the original problem, we get ∫x^3/(x^2+1)^(3/2) dx = ∫x^2/(x^2+1)^(3/2) (du/2x) = ∫u^(-3/2) (du/2) = u^(-1/2) + C = (x^2+1)^(-1/2) + C.

5. Are there any other methods to solve this integration problem?

Yes, there are other methods to solve this integration problem such as using trigonometric substitutions or partial fractions. However, the substitution method is the most straightforward and efficient method for this particular problem.

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