y=x/(x-8)=(x-8)/(x-8)+8/(x-8)=1+8/(x-8)
2y=2+16(x-8)
x+2y=x+2x/(x-8)=x+2+16/(x-8)=x-8+10+16/(x-8)=(x-8)+16/(x-8)+10
已知正数xy满足8/x+1/y=1,则x+2y的最小值是多少?问:这一步怎么来的
已知正数xy满足8/x+1/y=1,则x+2y的最小值是多少?问:这一步怎么来的
8/x+1/y=1
1/y=1-8/x=(x-8)/x
y=x/(x-8)
x+2y=x+2x/(x-8)=x+2+16/(x-8)=(x-8)+16/(x-8)+10
≥2√[(x-8)*16/(x-8)]+10=2√16+10=18
x+2y的最小值是18
问,这一步怎么来的:x+2x/(x-8)=x+2+16/(x-8)=(x-8)+16/(x-8)+10
8/x+1/y=1
1/y=1-8/x=(x-8)/x
y=x/(x-8)
x+2y=x+2x/(x-8)=x+2+16/(x-8)=(x-8)+16/(x-8)+10
≥2√[(x-8)*16/(x-8)]+10=2√16+10=18
x+2y的最小值是18
问,这一步怎么来的:x+2x/(x-8)=x+2+16/(x-8)=(x-8)+16/(x-8)+10
数学人气:904 ℃时间:2019-08-22 12:52:04
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