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来源：学生作业帮助网 编辑：六六作业网 时间：2024/07/06 17:53:21
xxxx＜5/4===>5-4x>0y=4x-2+1/(4x-5)=4x-5+1/(4x-5)+3=-[5-4x+1/(5-4x)]+35-4x+1/(5-4x)>=2√(5-4x)*1/(5-4x2
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x＜5/4 ===>5-4x>0
y=4x-2+1/(4x-5)
=4x-5+1/(4x-5)+3
=-[5-4x+1/(5-4x)]+3
5-4x+1/(5-4x)>=2√(5-4x)*1/(5-4x2)=2 (当且仅当5-4x=1/(5-4x）取到等号）
ymax=-2+3=1