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Math Help - Integral problem

  1. #1
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    Integral problem

    Find the intregral of:

    The square root of (1+x^3)

    I've tried this for a while, it's tough. Perhaps im missing something.
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  2. #2
    Super Member wingless's Avatar
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    \int \sqrt{x^3 + 1}~dx

    This integral seems messy. I couldn't come up with a nice way to evaluate.
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  3. #3
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    The thing is: it can't be computed in elementary terms.
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  4. #4
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    Question

    Am I missing something here?

    [insert huge great big mathematical flaw]

    see post below
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  5. #5
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    That's one of the terrible mistakes that a human been can ever do!

    \sqrt{a+b}\ne\sqrt a+\sqrt b.

    And please, reduce the size of your image.

    (Quite amazing how people covering integration makes those mistakes.)
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  6. #6
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    hmm

    So this cannot be done easily? The person i'm helping is a senior in HS taking AP calc. 1, so really only u sub seems viable.
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  7. #7
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    Replace the "cannot be done easily" by "it can't be done." You may try substitutions, integration by parts but you can't get an easy integral to get rid of the problem.
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  8. #8
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Krizalid View Post
    That's one of the terrible mistakes that a human been can ever do!
    i agree. but it's human "being"

    (don't worry, a lot of native english speakers don't know that -- funny huh?)
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  9. #9
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    Quote Originally Posted by Jhevon View Post
    (don't worry, a lot of native english speakers don't know that -- funny huh?)
    Ohhh, I felt stupid

    If you said so, then it's common
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  10. #10
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Krizalid View Post
    Ohhh, I felt stupid

    If you said so, then it's common
    yes, i make fun of people about it all the time. except i usually interpret it as them saying "bean"

    "wow, you saw a human bean?! that's amazing! just like those walking raisins in that old cartoon show (i forgot what it was called)"

    anyway, i always imagine a bean with arms, legs and a face walking down the street
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  11. #11
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    Quote Originally Posted by bakeit1 View Post
    So this cannot be done easily? The person i'm helping is a senior in HS taking AP calc. 1, so really only u sub seems viable.
    Where has the question come from? Is there a typo - should it be x^2, not x^3? Is it a definite integral where only an approximate answer is required?

    The complete context is essential in questions like this.

    My money's on the typo scenario ....
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  12. #12
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by Krizalid View Post
    Replace the "cannot be done easily" by "it can't be done." You may try substitutions, integration by parts but you can't get an easy integral to get rid of the problem.
    Bah! Someday someone will finally expand the meaning of the term "elementary function" and we'll be able to compute this exactly.

    -Dan
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  13. #13
    Math Engineering Student
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    That'd be nice really, but I do prefer solving nice & interesting problems (Tough ones, of course.)
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  14. #14
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    Quote Originally Posted by bakeit1 View Post
    Find the intregral of:

    The square root of (1+x^3)

    I've tried this for a while, it's tough. Perhaps im missing something.
    Quote Originally Posted by bakeit1 View Post
    So this cannot be done easily? The person i'm helping is a senior in HS taking AP calc. 1, so really only u sub seems viable.
    You be the judge:
    Attached Thumbnails Attached Thumbnails Integral problem-msp8.gif  
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  15. #15
    Forum Admin topsquark's Avatar
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    That's an easy expression to derive. (NOT)

    What's the function F? Some variation on the hypergeometric function?

    -Dan
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