So I just started taking an intro diff eq course and here's one of my hw problems:(adsbygoogle = window.adsbygoogle || []).push({});

"Determine whether the given first-order diff eq is linear in the indicated dependent variable."

(y^{2}-1)dx + xdy=0; in y; in x

I got the whole bit about the general form for linearity but I was thrown off by having just a 'dx' and 'dy' instead of the more familiar 'dy/dx'

(answer to the question is non linear when y is dependant, linear when x is dependant)

I'm confused as to what exactly 'dy' or 'dx' means, both conceptually and mathematically. I have a feeling there's a nice thread on this somewhere...

thanks for the help!

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# Homework Help: Determining linearity

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