extreme f(xy)=4-x^2-2y^2

解答

极值点

f (x y) = 4 - x^{2} - 2 y^{2}

极大值 (0, 0)

求解步骤

找到临界点:

(0, 0)

\frac{\partial ^{2} f}{\partial x ^{2}} = - 4

D (x, y) = 8

检查在每个临界点处的符号

检查临界点

(0, 0) :

极大值

极大值 (0, 0)

e x t re m e f (x, y) = x^{3} - 12 x + y^{2} + 6 y + 14

e x t re m e \frac{x - 5}{4}

e x t re m e f (x, y) = x^{2} + y^{2} - 18 x + 16 y - 7

e x t re m e f (x) = 7 x - 14 cos (x), - 2 \leq x \leq 0

e x t re m e f (x) = 3 x, - 27 \leq x \leq 27