## Differentiate with substitution [closed]

Hello Let's say you have the following formula: $f(x)=\frac{dy}{dx}x$ And earlier you made the following substitution: $x=2n$ If you plug this in $f(x)$, I think you would get the following: $f(2n)=\frac{1}{2}\frac{dy}{dn}2n$ My question is: Is this true?

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Yes but please note that this site is devoted to reseach questions. Please check the FAQ, where you may also find links to other sites that are more suitable for your question. – Pietro Majer Jan 15 2012 at 13:43