Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.soft-sys.math.maple > #307 > unrolled thread

int(exp(x^n),x) and Ei

Back to article view | Back to comp.soft-sys.math.maple

Contents

  int(exp(x^n),x) and Ei "Thomas D. Dean" <tomdean@speakeasy.org> - 2012-01-13 13:13 -0800
    Re: int(exp(x^n),x) and Ei Axel Vogt <&noreply@axelvogt.de> - 2012-01-14 09:17 +0100
    Re: int(exp(x^n),x) and Ei "G. A. Edgar" <edgar@math.ohio-state.edu.invalid> - 2012-01-14 06:59 -0700
    Re: int(exp(x^n),x) and Ei Peter Pein <petsie@dordos.net> - 2012-01-14 20:40 +0100
      Re: int(exp(x^n),x) and Ei "G. A. Edgar" <edgar@math.ohio-state.edu.invalid> - 2012-01-15 06:45 -0700

#307 — int(exp(x^n),x) and Ei

Wolfram gives the result of

integrate(exp(x^n),x) as

integrate(exp(x^n),x) = -x*Ei[(n-1)/n](-x^n)/n

http://integrals.wolfram.com/index.jsp?expr=exp(x^n)&random=false

Maple just returns the original expression.

How do I get the Ei form?

Tom Dean

[toc] | [next] | [standalone]

#309

On 13.01.2012 22:13, Thomas D. Dean wrote:
> Wolfram gives the result of
>
> integrate(exp(x^n),x) as
>
> integrate(exp(x^n),x) = -x*Ei[(n-1)/n](-x^n)/n
>
> http://integrals.wolfram.com/index.jsp?expr=exp(x^n)&random=false
>
> Maple just returns the original expression.
>
> How do I get the Ei form?
>
> Tom Dean

There should be no integration variable in the result.

[toc] | [prev] | [next] | [standalone]

#312

In article <0q6dnULAAoXiA43SnZ2dnUVZ_oWdnZ2d@megapath.net>, Thomas D.
Dean <tomdean@speakeasy.org> wrote:

> Wolfram gives the result of
> 
> integrate(exp(x^n),x) as
> 
> integrate(exp(x^n),x) = -x*Ei[(n-1)/n](-x^n)/n
> 
> http://integrals.wolfram.com/index.jsp?expr=exp(x^n)&random=false
> 
> Maple just returns the original expression.
> 
> How do I get the Ei form?

I think you cannot do that in Maple.  That E with subscript is just a
re-writing of the original integral anyway... and Maple does not
include that variant.  Using an actual value for n, Maple can produce
the incomplete Gamma versions...

integrate(exp(x^7),x)
after simplifying gets me to
(1/7)*exp(-((1/7)*I)*Pi)*(GAMMA(1/7)-GAMMA(1/7, -x^7))
and you can of course adjust the constant of integration.
So, interestingly, both Maple and Alpha use complex numbers to
represent this real integral.

-- 
G. A. Edgar                              http://www.math.ohio-state.edu/~edgar/

[toc] | [prev] | [next] | [standalone]

#313

Am 13.01.2012 22:13, schrieb Thomas D. Dean:
> Wolfram gives the result of
>
> integrate(exp(x^n),x) as
>
> integrate(exp(x^n),x) = -x*Ei[(n-1)/n](-x^n)/n
>
> http://integrals.wolfram.com/index.jsp?expr=exp(x^n)&random=false
>
> Maple just returns the original expression.
>
> How do I get the Ei form?
>
> Tom Dean

convert("-x*Ei[(n-1)/n](-x^n)/n", FromMma);

[toc] | [prev] | [next] | [standalone]

#314

In article <jeslnl$8f4$1@online.de>, Peter Pein <petsie@dordos.net>
wrote:

> Am 13.01.2012 22:13, schrieb Thomas D. Dean:
> > Wolfram gives the result of
> >
> > integrate(exp(x^n),x) as
> >
> > integrate(exp(x^n),x) = -x*Ei[(n-1)/n](-x^n)/n
> >
> > http://integrals.wolfram.com/index.jsp?expr=exp(x^n)&random=false
> >
> > Maple just returns the original expression.
> >
> > How do I get the Ei form?
> >
> > Tom Dean
> 
> convert("-x*Ei[(n-1)/n](-x^n)/n", FromMma);

maybe...

convert("-x*Ei[(n-1)/n,-x^n]/n", FromMma);

But even if Maple returns something, it doesn't know what it is.

-- 
G. A. Edgar                              http://www.math.ohio-state.edu/~edgar/

[toc] | [prev] | [standalone]

Back to top | Article view | comp.soft-sys.math.maple

csiph-web