I am able to proove to myself, through generalised substitution, that the integral of f'(x)/f(x) is lnf(x)+c, but where do the modulus signs come from? ie - The accepted integral is ln|f(x)|+c, not lnf(x)+c(adsbygoogle = window.adsbygoogle || []).push({});

Thanks in advance.

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# Why the modulus signs when integrating f'(x)/f(x)?

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