# Math Help - Stationary points

1. ## Stationary points

Prove that the polynomial

$f=(x^2+y^2)(x^2+y^2+1)z+z^3+x+y$

doesn't have real stationary points.

Thanks!!!

2. Originally Posted by roporte
Prove that the polynomial

$f=(x^2+y^2)(x^2+y^2+1)z+z^3+x+y$

doesn't have real stationary points.

Thanks!!!
Start by calculating the partial derivatives and equating them to zero. Can you do that? Post your answers.