假設有A,B兩集合 映成(onto)函數是 代表說 B 裡每個元素都能被 A 裡元素對應到 映至(into)函數是 A 裡每一元素都剛好有 B 裡的元素對應 那說例兩題是怎麼知道是映成還是映至呢⋯⋯

說例 f:避一航by y=(X) 三太 Range=fy|y>0ycR}cB fis into 際例 f:朋一[0oo)by y=f(x) =x Range =1y|y>0,ycR) =B f1s ohto

求解第18題

上GIUMeS ot 2, and > that maximize 2y十372z十 23. Tindt 3y2 SubjJect to eeonStraint 9 一 ?yz 二0. KM - 了 蟬 罷d the Values Of 寢, ?, > that rmaXxlrnmlze 二

求解

(b) (15%) Use the method of Lagrange multipliers to find the extreme values: 7 立 subject_ to the constITaint 多十少三 4.

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