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PARI/gp
#1
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.
Xorter Unizo
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#2
(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)
?
Gottfried Helms, Kassel
Reply
#3
(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.
Xorter Unizo
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#4
But somewhy it does not work with gamma function. Sad
Xorter Unizo
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#5
(04/17/2017, 07:05 PM)Xorter Wrote: But somewhy it does not work with gamma function. Sad

sin(x+1) or gamma(x+1)
- Sheldon
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#6
(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. Sad

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
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#7
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
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#8
(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
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#9
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
Reply
#10
(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
Reply


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