# Tetration Forum

Full Version: PARI/gp
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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):
Code:
`subst(sin(x),x,1)`
But it returns with error. Why? Please, help me.
(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):
Code:
`subst(sin(x),x,1)`
But it returns with error. Why? Please, help me.

Code:
`subst(Pol(sin(x)),x,1)`
should work. But why not simply do
Code:
`sin(1)`
?
(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):
Code:
`subst(sin(x),x,1)`
But it returns with error. Why? Please, help me.

Code:
`subst(Pol(sin(x)),x,1)`
should work. But why not simply do
Code:
`sin(1)`
?

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

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