解由1/X+2/Y
=(1/X+2/Y)×1
=(1/X+2/Y)×（x+2Y）/3
=1/3(1/X+2/Y)×（x+2Y）
=1/3(1+4+2x/Y+2Y/X)
=5/3+1/3(2X/Y+2Y/X)
≥5/3+1/3×2√2X/Y×2Y/X
=5/3+4/3
=3
故
1/X+2/Y的最小值为3.
猜你喜欢
- 1所有自然数的公因数是_．
- 2First,I get up early.Next,I brush my teeth and comb my hair.After thet,I eat breakfast.
- 3薛谭乃谢求反 反的意思
- 4She spends a lot of time with them.
- 5黄果树瀑布课文里有哪几句比喻句,什么比作什么呢?
- 6小数部分的位数是什么的小数
- 7停止沸腾的水,浇上冷水后会沸腾是什么原因
- 8难忘的那一刻500字作文
- 9You would not have been robbed if you had taken me as your company.
- 10已知函数f(x)=1/3x的平方+2x的平方-5