Re: Sum of powers of multiplied terms
- To: mathgroup at smc.vnet.net
- Subject: [mg117758] Re: Sum of powers of multiplied terms
- From: Peter Pein <petsie at dordos.net>
- Date: Thu, 31 Mar 2011 03:58:08 -0500 (EST)
- References: <imuse8$i9k$1@smc.vnet.net>
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]]]}] ]
?