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Hi, again!

I need your help in PARI/gp. I would like to substitute a value into x of sin(x):

But it returns with error. Why? Please, help me.

Xorter Unizo

Posts: 752

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Joined: Aug 2007

(04/17/2017, 09:48 AM)Xorter Wrote: Hi, again!

I need your help in PARI/gp. I would like to substitute a value into x of sin(x):

But it returns with error. Why? Please, help me.

Code:

`subst(Pol(sin(x)),x,1)`

should work. But why not simply do

?

Gottfried Helms, Kassel

Posts: 76

Threads: 25

Joined: Aug 2016

04/17/2017, 05:53 PM
(This post was last modified: 04/17/2017, 05:54 PM by Xorter.)
(04/17/2017, 04:27 PM)Gottfried Wrote: (04/17/2017, 09:48 AM)Xorter Wrote: Hi, again!

I need your help in PARI/gp. I would like to substitute a value into x of sin(x):

But it returns with error. Why? Please, help me.

Code:

`subst(Pol(sin(x)),x,1)`

should work. But why not simply do

?

Oh, it was simplier than I thought. Thank you, my friend!

Well, because I have found a new type of integration and derivation. These are iterated! And I needed substitution in a function in my gp. Really amazing. I am going to share my results on this forum as soon as possibly.

(May be the key to determine what between addition and multiplication is.)

Just wait a few days, please.

Xorter Unizo

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Joined: Aug 2016

But somewhy it does not work with gamma function.

Xorter Unizo

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(04/17/2017, 07:05 PM)Xorter Wrote: But somewhy it does not work with gamma function.

sin(x+1) or gamma(x+1)

- Sheldon

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(04/18/2017, 05:37 AM)sheldonison Wrote: (04/17/2017, 07:05 PM)Xorter Wrote: But somewhy it does not work with gamma function.

sin(x+1) or gamma(x+1)

I have determined the graphs with sin functions, but now I would like to work with gamma, too.

These methods are the generalizations of the integration and derivation...

Xorter Unizo

Posts: 76

Threads: 25

Joined: Aug 2016

Hi, again!

Here is another problem. I would like to calculate this productum but without success:

Code:

`subst(exp(1/x),x,1/1000)`

Why?

Xorter Unizo

Posts: 752

Threads: 114

Joined: Aug 2007

(11/20/2017, 08:21 PM)Xorter Wrote: Hi, again!

Here is another problem. I would like to calculate this productum but without success:

Code:

`subst(exp(1/x),x,1/1000)`

Why?

The error message in my (old) Pari/GP-system is

Quote:exp(1/'x)

*** exp: negative exponent in gexp.

I don't think they have anything new implemented for this problem so far.

Gottfried Helms, Kassel

Posts: 76

Threads: 25

Joined: Aug 2016

I got the following error message:

*** at top-level: subst(exp(1/x),x,1/1000)

*** ^------------------

*** exp: domain error in exp: valuation < 0

My question is that how can we solve this problem?

Xorter Unizo

Posts: 752

Threads: 114

Joined: Aug 2007

(11/21/2017, 01:31 PM)Xorter Wrote: I got the following error message:

*** at top-level: subst(exp(1/x),x,1/1000)

*** ^------------------

*** exp: domain error in exp: valuation < 0

My question is that how can we solve this problem?

Perhaps it is meaningful for you to replace 1/x by exp(-u) where u=log(x) ? At least this gives a power series (more precisiely a puisieux-series)

Gottfried Helms, Kassel