Nalezn�te maximum a minimum funkce $f$ na mno�in� $K.$
Zd�vodn�te v�sledek!
$$
f(x,y) = x - 2y - 3, \qquad
K = \{[x,y] \in \Bbb R^2; \, x \in [0,1], y \in [0,1], x + y \in
[0,1] \}; \\
$$

$$
f(x,y) = e^{-(x^2 + y^2)}(2x^2 + 3y^2), \qquad
K = \{[x,y] \in \Bbb R ^2; \, x^2 + y^2 \leq \frac {1}{16}\}; \\
$$

$$
f(x,y) = 3xy + \log (1 + x^2 + y^2), \qquad
K = \{[x,y] \in \Bbb R^2; \, 1 \leq x^2 + y^2 \leq 4 \}.
$$
