Collect Fourier series terms












3












$begingroup$


Is there a way to make mathematica automatically collect terms like $mathrm{Cos}[n x]$ with $n=1,2,3...$?
I have a long expression coming out of a Fourier series where I see a lot of $Cos[x],Cos[2 x],Cos[3 x]$ and so on, but Simplify is very inefficient. I would like mathematica to automatically collect all coefficients of the various Cos[n x] without having to do it manually for each one of them.






coefficients







share|improve this question









$endgroup$












  • $begingroup$
    can you show your initial code, so we try to help!
    $endgroup$
    – Alrubaie
    2 days ago










  • $begingroup$
    Try Collect[exp /. Cos[x n_.] -> x^n, x]/. x^n_. -> Cos[n x].
    $endgroup$
    – Somos
    2 days ago


















3












$begingroup$


Is there a way to make mathematica automatically collect terms like $mathrm{Cos}[n x]$ with $n=1,2,3...$?
I have a long expression coming out of a Fourier series where I see a lot of $Cos[x],Cos[2 x],Cos[3 x]$ and so on, but Simplify is very inefficient. I would like mathematica to automatically collect all coefficients of the various Cos[n x] without having to do it manually for each one of them.






coefficients







share|improve this question









$endgroup$












  • $begingroup$
    can you show your initial code, so we try to help!
    $endgroup$
    – Alrubaie
    2 days ago










  • $begingroup$
    Try Collect[exp /. Cos[x n_.] -> x^n, x]/. x^n_. -> Cos[n x].
    $endgroup$
    – Somos
    2 days ago
















3












3








3





$begingroup$


Is there a way to make mathematica automatically collect terms like $mathrm{Cos}[n x]$ with $n=1,2,3...$?
I have a long expression coming out of a Fourier series where I see a lot of $Cos[x],Cos[2 x],Cos[3 x]$ and so on, but Simplify is very inefficient. I would like mathematica to automatically collect all coefficients of the various Cos[n x] without having to do it manually for each one of them.






coefficients







share|improve this question









$endgroup$




Is there a way to make mathematica automatically collect terms like $mathrm{Cos}[n x]$ with $n=1,2,3...$?
I have a long expression coming out of a Fourier series where I see a lot of $Cos[x],Cos[2 x],Cos[3 x]$ and so on, but Simplify is very inefficient. I would like mathematica to automatically collect all coefficients of the various Cos[n x] without having to do it manually for each one of them.






coefficients




coefficients






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked 2 days ago









RiccardoRiccardo

505




505












  • $begingroup$
    can you show your initial code, so we try to help!
    $endgroup$
    – Alrubaie
    2 days ago










  • $begingroup$
    Try Collect[exp /. Cos[x n_.] -> x^n, x]/. x^n_. -> Cos[n x].
    $endgroup$
    – Somos
    2 days ago




















  • $begingroup$
    can you show your initial code, so we try to help!
    $endgroup$
    – Alrubaie
    2 days ago










  • $begingroup$
    Try Collect[exp /. Cos[x n_.] -> x^n, x]/. x^n_. -> Cos[n x].
    $endgroup$
    – Somos
    2 days ago


















$begingroup$
can you show your initial code, so we try to help!
$endgroup$
– Alrubaie
2 days ago




$begingroup$
can you show your initial code, so we try to help!
$endgroup$
– Alrubaie
2 days ago












$begingroup$
Try Collect[exp /. Cos[x n_.] -> x^n, x]/. x^n_. -> Cos[n x].
$endgroup$
– Somos
2 days ago






$begingroup$
Try Collect[exp /. Cos[x n_.] -> x^n, x]/. x^n_. -> Cos[n x].
$endgroup$
– Somos
2 days ago












1 Answer
1






active

oldest

votes


















5












$begingroup$

is this what you are asking? 



exp=3Cos[x]+5Cos[2x]+12Cos[3x];



Coefficient[exp,Cos[x #]]&/@Range@3



{3, 5, 12}







share|improve this answer











$endgroup$













  • $begingroup$
    Yes, thanks this is it!
    $endgroup$
    – Riccardo
    2 days ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    2 days ago












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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









5












$begingroup$

is this what you are asking? 



exp=3Cos[x]+5Cos[2x]+12Cos[3x];



Coefficient[exp,Cos[x #]]&/@Range@3



{3, 5, 12}







share|improve this answer











$endgroup$













  • $begingroup$
    Yes, thanks this is it!
    $endgroup$
    – Riccardo
    2 days ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    2 days ago
















5












$begingroup$

is this what you are asking? 



exp=3Cos[x]+5Cos[2x]+12Cos[3x];



Coefficient[exp,Cos[x #]]&/@Range@3



{3, 5, 12}







share|improve this answer











$endgroup$













  • $begingroup$
    Yes, thanks this is it!
    $endgroup$
    – Riccardo
    2 days ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    2 days ago














5












5








5





$begingroup$

is this what you are asking? 



exp=3Cos[x]+5Cos[2x]+12Cos[3x];



Coefficient[exp,Cos[x #]]&/@Range@3



{3, 5, 12}







share|improve this answer











$endgroup$



is this what you are asking? 



exp=3Cos[x]+5Cos[2x]+12Cos[3x];



Coefficient[exp,Cos[x #]]&/@Range@3



{3, 5, 12}








share|improve this answer














share|improve this answer



share|improve this answer








edited 2 days ago

























answered 2 days ago









J42161217J42161217

4,273324




4,273324












  • $begingroup$
    Yes, thanks this is it!
    $endgroup$
    – Riccardo
    2 days ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    2 days ago


















  • $begingroup$
    Yes, thanks this is it!
    $endgroup$
    – Riccardo
    2 days ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    2 days ago
















$begingroup$
Yes, thanks this is it!
$endgroup$
– Riccardo
2 days ago




$begingroup$
Yes, thanks this is it!
$endgroup$
– Riccardo
2 days ago












$begingroup$
you are welcome!
$endgroup$
– J42161217
2 days ago




$begingroup$
you are welcome!
$endgroup$
– J42161217
2 days ago


















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