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

Groups > comp.soft-sys.math.mathematica > #1288 > unrolled thread

Sum of powers of multiplied terms

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

Contents

  Sum of powers of multiplied terms Chelly <chelly85086@gmail.com> - 2011-03-30 09:16 +0000
    Re: Sum of powers of multiplied terms Peter Pein <petsie@dordos.net> - 2011-03-31 08:58 +0000

#1288 — Sum of powers of multiplied terms

I am new to Mathematica and need some help on the following:

I have a variable which has a sum of many sine terms as shown below:

x = k1^2 k2^2 e^2 Sin(phi) + k3^2 e k4^2 Sin(theta) +....

I'd like to create a table where the first element is the index of the list and the second element is the sum of the powers of the amplitude terms. In this case, I'd like it to be

{1,6},{2,5}

where the sum of powers of the first amplitude term is 2+2+2=6, and similarly for the second term it is 2+1+2=5

Thanks
Chelly

[toc] | [next] | [standalone]

#1302

Am 30.03.2011 11:16, schrieb Chelly:
> I am new to Mathematica and need some help on the following:
>
> I have a variable which has a sum of many sine terms as shown below:
>
> x = k1^2 k2^2 e^2 Sin(phi) + k3^2 e k4^2 Sin(theta) +....
>
> I'd like to create a table where the first element is the index of the list and the second element is the sum of the powers of the amplitude terms. In this case, I'd like it to be
>
> {1,6},{2,5}
>
> where the sum of powers of the first amplitude term is 2+2+2=6, and similarly for the second term it is 2+1+2=5
>
> Thanks
> Chelly
>

something like

Block[{k=0},
   Cases[x, a_. Sin[_] :> {++k, Total[Exponent[a, Variables[a]]]}] ]

?

[toc] | [prev] | [standalone]

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

csiph-web