I just don't get why the method of undetermined coefficients can't be applied to tan(x) and sec(x). What my book says is this-(adsbygoogle = window.adsbygoogle || []).push({});

"Since the number of terms applied by differentiating tan(x) and sec(x) is infinity".

What do they mean by that? Even the number of terms obtained by differentiating sin(x) is infinity but the method of undetermined coefficients still works for sin(x).

I would be really happy if you could clear me this doubt

Thanks a lot :)

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# P.I of tanx and secx using Undetermined coefficients

**Physics Forums | Science Articles, Homework Help, Discussion**