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Math Help - integral 2/sqrt(x^2-4)

  1. #1
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    integral 2/sqrt(x^2-4)

    i keep getting 2ln|(x/2)-(sqrt(x^2-4)/2)|+c but the the correct answer isnt divided by two inside the ln.
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by cmm1863 View Post
    i keep getting 2ln|(x/2)-(sqrt(x^2-4)/2)|+c but the the correct answer isnt divided by two inside the ln.
    See what WolframAlpha does (though you may want to put absolute values in the logs):

    Attached Thumbnails Attached Thumbnails integral 2/sqrt(x^2-4)-gash.jpg  
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  3. #3
    Grand Panjandrum
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    Quote Originally Posted by cmm1863 View Post
    i keep getting 2ln|(x/2)-(sqrt(x^2-4)/2)|+c but the the correct answer isnt divided by two inside the ln.
    You can multiply inside the log by whatever you want, it results in a different additive constant at the end:

    \ln(k f(x))=\ln(f(x))+\ln(k)

    CB
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