Calculus/Integration techniques/Irrational Functions

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Integration techniques/Irrational Functions

Integration of irrational functions is more difficult than rational functions, and many cannot be done. However, there are some particular types that can be reduced to rational forms by suitable substitutions.

Type 1

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Integrand contains  

Use the substitution   .

Example

Find   .

Find   .

Type 2

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Integral is of the form  

Write   as   .

Example

Find   .

Type 3

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Integrand contains   ,   or  

This was discussed in "trigonometric substitutions above". Here is a summary:

  1. For   , use   .
  2. For   , use   .
  3. For   , use   .

Type 4

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Integral is of the form  

Use the substitution   .

Example

Find   .

Type 5

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Other rational expressions with the irrational function  

  1. If   , we can use   .
  2. If   , we can use   .
  3. If   can be factored as   , we can use   .
  4. If   and   can be factored as   , we can use  
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Integration techniques/Irrational Functions