Hi

Evaluate:

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- Mar 16th 2010, 11:44 AMShockquite difficult integral
Hi

Evaluate:

- Mar 16th 2010, 12:26 PMGeneral
**Dangerous one.**

**See:**

**http://www.wolframalpha.com/input/?i=integrate+1%2Fsqrt%28x%28x%5E2%2B1%29%29** - Mar 16th 2010, 12:49 PMShock
I've 2 different solutions:

1) This

http://integrals.wolfram.com/index.jsp?expr=1%2F(x*Sqrt[x^2+%2B1])

2) And this (provided by my professor)

- Mar 16th 2010, 12:57 PMGeneral
**Use the substitution ..**

**to get (with some trig-identities):**

**Integration by parts maybe?** - Mar 16th 2010, 01:23 PMDefunkt
- Mar 16th 2010, 02:13 PMchisigma
Probably an elementary primitive of the function doesn't exist, so that we can try to obtain at least a series expansion of it. Let's start with...

(1)

... where and...

(2)

... and, performing integration, we obtain...

(3)

Kind regards