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Groups > comp.soft-sys.math.mathematica > #2646

Re: get a, b from numbers in the form a+b Pi

From Heike Gramberg <heike.gramberg@gmail.com>
Newsgroups comp.soft-sys.math.mathematica
Subject Re: get a, b from numbers in the form a+b Pi
Date 2011-05-23 10:28 +0000
Organization Steven M. Christensen and Associates, Inc and MathTensor, Inc.
Message-ID <irdcsl$3se$1@smc.vnet.net> (permalink)

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You could try something like

CoefficientList[nums, Pi]

Heike.

On 22 May 2011, at 11:57, 1.156 wrote:

> I have lists  of numbers (Mathematica output) all numerically in the 
> form a + b*Pi and I'm trying to extract the values of a and b for 
> further work.
> 
> Here's an example of the best I've been able to do so far:
> 
> nums={1/2 (-2+\[Pi]),-2+(3 \[Pi])/4,-(11/3)+(5 \[Pi])/4,5/48 (-64+21 
> \[Pi]),-(61/5)+(63 \[Pi])/16,-(338/15)+(231 \[Pi])/32};
> {FullForm[#][[1,1]],FullForm[#][[1,2]]/\[Pi]}&/@nums
> 
> When I run this line of code 4 of the six input numbers give me the 
> {a,b} I'm looking for but the first and fourth entries fail because the 
> form isn't right. Possibly I could patch this scheme to look for a small 
> finite set of possibilities of input number form but I suspect I may a 
> long way from attacking this problem correctly.
> 
> Can someone offer some other ideas on how to pull this off? Many thanks 
> for looking at this. Rob
> -- 
> Sent from my plain desktop PC.
> 

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Re: get a, b from numbers in the form a+b Pi Heike Gramberg <heike.gramberg@gmail.com> - 2011-05-23 10:28 +0000

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