推 darkstar0412:感謝....不過看不懂Orz 220.134.79.28 03/26 21:47
→ darkstar0412:懂了 剛剛一時腦殘^^ 220.134.79.28 03/26 21:51
推 ElvinN:原來是如此!我英文太差了Orz 118.165.92.252 03/26 22:10
※ 引述《darkstar0412 (目標當個米蟲廢物公務員)》
: 4.y=2x-10 ,find the values for xand y such that thier product is a minimun.
y=2x-10
=>(y+10)/2=x
=>(y^2+10y)/2 =xy
=>xy=(y^2+10y)/2 ={(y+5)^2-25}/2 >= -25/2
等號在y=-5時成立 代入 y=2x-10 得x=5/2
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