Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Number 65 in asks to find the graphs possible curves that satisfy the differential equation

$(\frac{dy}{dx})^2 + 2y \frac{dy}{dx} + y^2 = 0$

What method is used to solve this differential equation?

share|cite|improve this question
up vote 8 down vote accepted

The given equation can be rewritten as: $$ \left( \frac{dy}{dx} + y \right)^2 = 0. $$

You should be able to go from here, assuming you know how to solve first order linear differential equations. I don't want to spoil the fun too much! :-)

share|cite|improve this answer
Why community wiki? Why not accept credit where credit is due? – Gerry Myerson Oct 12 '11 at 5:07
@Gerry The official reason is that it seemed too simple (plus, I didn't want to give out the full answer). For the actual reason, please take a look at my reputation points. I am trying to enjoy it while it lasts. :-) – Srivatsan Oct 12 '11 at 5:10
Well, but the more credit you accept, the quicker you'll get to 6666. – Gerry Myerson Oct 12 '11 at 6:10
@Gerry I see your point. In fact, after writing that comment, I felt guilty of being frivolous, so I wrote an answer to some other question so that I could 'move on' :). Thanks for the push anyway. – Srivatsan Oct 12 '11 at 6:27

Your Answer


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

Not the answer you're looking for? Browse other questions tagged or ask your own question.