Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Solve :

$$y=p \log p + \log(\cos p)$$ where $p$ is $dy/dx$

Solving for $p$ I get in my equation $\tan p/p$ which I am not sure how to solve. Help please !

Also,is there something that I'm missing , like prolly an easier way to go about this. Thanks!

share|improve this question
Hint: This is Lagrange's differential equation, with $\varphi \equiv 0$. –  user1337 Dec 4 '13 at 17:43
the form of lagrange's equation is y=xf(y') + g(y') but there's no x in the above eqn , right? –  user113051 Dec 4 '13 at 18:55
that's why you should take $f(y')=0$. –  user1337 Dec 4 '13 at 21:24

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.