Collect Fourier series terms












2












$begingroup$


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







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$endgroup$












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










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


















2












$begingroup$


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
    12 hours ago










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
















2












2








2





$begingroup$


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 12 hours ago









RiccardoRiccardo

455




455












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










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




















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










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


















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




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












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






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












1 Answer
1






active

oldest

votes


















3












$begingroup$

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
    11 hours ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    11 hours ago












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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









3












$begingroup$

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
    11 hours ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    11 hours ago
















3












$begingroup$

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
    11 hours ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    11 hours ago














3












3








3





$begingroup$

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 11 hours ago

























answered 11 hours ago









J42161217J42161217

4,248324




4,248324












  • $begingroup$
    Yes, thanks this is it!
    $endgroup$
    – Riccardo
    11 hours ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    11 hours ago


















  • $begingroup$
    Yes, thanks this is it!
    $endgroup$
    – Riccardo
    11 hours ago










  • $begingroup$
    you are welcome!
    $endgroup$
    – J42161217
    11 hours ago
















$begingroup$
Yes, thanks this is it!
$endgroup$
– Riccardo
11 hours ago




$begingroup$
Yes, thanks this is it!
$endgroup$
– Riccardo
11 hours ago












$begingroup$
you are welcome!
$endgroup$
– J42161217
11 hours ago




$begingroup$
you are welcome!
$endgroup$
– J42161217
11 hours ago


















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