原式=(x+y)/(√x-√y)-(2xy)/(x√y-y√x)
=(x+y)/(√x-√y)-(2xy)/[√(xy)(√x-√y)]
=(x+y)/(√x-√y)-2√(xy)/(√x-√y)]
=[(x+y)-2√(xy)]/(√x-√y)
=[x-2√(xy)+y]/(√x-√y)
=(√x-√y)²/(√x-√y)
=√x-√y
当x=8,y=18时
原式=√8-√18
=2√2-3√2
= -√2
已知当x=8,y=18,求(x+y)/(根号x-根号y)-(2xy)/(x根号y-y根号x)
已知当x=8,y=18,求(x+y)/(根号x-根号y)-(2xy)/(x根号y-y根号x)
数学人气:981 ℃时间:2019-11-15 20:17:05
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