
19.5.6 Compactness
condition: \[ A=\left\{(x, y) \mid x \geq 0, \quad 0 \leq y \leq \frac{x}{1+x^{4}}\right\} \] Is \( A \) compact? Show that the function \( f(x, y)=e^{x y} \) in \( A \) has a minimum and a maximum, what are they?