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Math Help - Trig Substitution

  1. #1
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    Trig Substitution

    The problem us integrate : \frac{1}{x \sqrt{x^2+25}}dx


    I worked it out to here
    <br /> <br /> <br />
\frac{5secT}{5tanT} dT


    1. Is this right so far and 2. Im a little confused on how to proceed from there.
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  2. #2
    Super Member Deadstar's Avatar
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    Well, ASSUMING what you did up to there was right then use...

    \sec(x) = \frac{1}{\cos(x)}

    and

    \tan(x) = \frac{\sin(x)}{\cos(x)}
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  3. #3
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    Good start. Extra factor of 5 in the numerator.
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  4. #4
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    Thats kind of what i thought so it should be \frac{secT}{5tanT}dT
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  5. #5
    Super Member Deadstar's Avatar
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    Quote Originally Posted by x5pyd3rx View Post
    Thats kind of what i thought so it should be \frac{secT}{5tanT}dT
    No the 5's cancel. 5/5 = 1...
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