Why am I getting stuck on these questions?
Find and classify the stationary points:
I forget how to find the roots. What to I need to revise? Any links?
It is not trivial and requires quite some tricky algebra:
If x = y then plugging into we get , else we plug and:
, and again or else ,
and doing the same with the other partial derivative we get that also
Nervertheless these last two values for x,y don't work, as you can check at once, so we're left with only...
Tonio