Hi,

my name is Dimos and I am coming from Greece.

Right to the point.

1) Can somebody help me with the:

ODE?

I ve tried to find a integration factor and change variable (e.g. v=2x*cos(y) ). I have no clue! Is this ODE a suitable example for polytechnics student?

2) Is there any higher order derivative test to find extrema of multi variable functions? Where can i find more details?

3) Can the use of Lagrange multipliers reveal the nature of extrema (i.e. is it a local minimum, local maximum or saddle point)? How?

Thank you in advance for any help!

Dimos

Athens.