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integration of sqrt of a cubic functions

(u)^(-1/2)dx where u=(5+4x-x^3)
Original post by Whyte-1
(u)^(-1/2)dx where u=(5+4x-x^3)


Hi, I've moved your thread to the maths forum where you'll hopefully receive some help.
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Whyte-1
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Thanks a bunch.
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Original post by Smack
Hi, I've moved your thread to the maths forum where you'll hopefully receive some help.


Hi is there a link I would go to check that forum.
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Original post by Whyte-1
(u)^(-1/2)dx where u=(5+4x-x^3)


I think this is likely to involve elliptic integals. In general you can't integrate square roots of cubics without use of special functions.
Original post by Whyte-1
(u)^(-1/2)dx where u=(5+4x-x^3)


Original post by RichE
I think this is likely to involve elliptic integals. In general you can't integrate square roots of cubics without use of special functions.
Wolfram gives a page-long expression involving both an elliptic integral and the 3 roots of the polynomial (which are all horrendous expressions in their own right).

Either the OP has made a mistake, or the integral is supposed to be found numerically.
1/sqrt(u)? Think about the relationship between a reciprocal and the logarithm.
Original post by rickyrossman
1/sqrt(u)? Think about the relationship between a reciprocal and the logarithm.
I suggest you explain what you mean; TBH I think you're confused (you've got 2 experienced graduates who don't think this has a solution in terms of elementary functions).

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