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Math Help - Integration

  1. #1
    Junior Member Selim's Avatar
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    Integration

    \int\frac{1}{3 + 2cos(x)}*dx let cos(x) = ?
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  2. #2
    MHF Contributor harish21's Avatar
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    Quote Originally Posted by Selim View Post
    \int\frac{1}{3 + 2cos(x)}*dx let cos(x) = ?
    See this link:

    integrate 1/(3+2cosx) - Wolfram|Alpha


    Click on "show steps"
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  3. #3
    Junior Member Selim's Avatar
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    How did they know to do that?
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  4. #4
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    mr fantastic's Avatar
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    Quote Originally Posted by Selim View Post
    How did they know to do that?
    It is a standard substitution known as the Weierstrass substitution. There are logical mathematical reasons for where it comes from but which are beyond the scope of what you're learning.
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