Differential equation with only the trivial solution

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
4 replies · 8K views
Bipolarity
Messages
773
Reaction score
2

Homework Statement


Find a differential equation with its only (complex-valued) solution being y=0

Homework Equations


The Attempt at a Solution


I believe that there is no DE having only y=0 as its solution, but frankly I am not sure if this is the case. I would like to know whether or not this is true, so that I know in which direction I can begin working my proof (or at least a hint is appreciated).

Also, something (in my mind) tells me this problem may have some connection with Wronskian matrices, but I have no clue really.

EDIT: I tried playing with some random diff Eqs, it seems that there are in fact trivial things like y+y'-y'=0, but this type of answer seems to be trivial to be of substance. Is there a DE that does not reduce to a trivial y=0?

Thanks!

BiP
 
Physics news on Phys.org
haruspex said:
One approach is to think of a function of y' that cannot be zero, f(y') say, then write f(y')y = 0.

Well, f(y')=1 works. Still seems like kind of a cheat. Notice they also said complex valued. So something like f(y')=1+(y')^2 won't work either. Not to say you can't cook one up. Like f(y')=(1+(y')(y'*)). I'm just wondering if there is something nontrivial here.
 
Last edited:
haruspex said:
I was thinking of ey'y=0

Good work! And thanks!

BiP