維爾斯特拉斯定理
(1) draw diagram of cases in which a feasible set (budget set) is not closed or not bunded,but a solution to the optimization problem exists.
(繪制圖的情況下,其中一個(gè)可行集（預(yù)算集）不閉合或不堤壆,但存在的最優(yōu)化問(wèn)題的解決方案)
(2)show f(x)=1,g(x)=x are continuous functions.
顯示函數(shù)f（x）= 1,G（X）=x是連續(xù)函數(shù)
(3)Does the following function has a maximum on the inverval [-1,1]?If not,explan why.
請(qǐng)問(wèn)以下函數(shù)有一個(gè)最大的區(qū)間[-1,1]?如果沒(méi)有,請(qǐng)解釋原因.
f(x)= 1/x,x=/=0；
0,x=0.