比较下列一组中两个代数式大小(x²+y²)(x-y)与(x²-y²)(x+y)(x>y>0)
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比较下列一组中两个代数式大小(x²+y²)(x-y)与(x²-y²)(x+y)(x>y>0)
比较下列一组中两个代数式大小
(x²+y²)(x-y)与(x²-y²)(x+y)(x>y>0)
比较下列一组中两个代数式大小(x²+y²)(x-y)与(x²-y²)(x+y)(x>y>0)
解(x²+y²)(x-y)-(x-y)(x+y)(x+y)
=(x-y)【(x²+y²)-(x+y)(x+y)】
=(x-y)【(x²+y²)-x²-y²-2xy】
=(x-y)【-2xy】
由x>y>0
即x-y>0,-2xy<0
即
(x-y)【-2xy】<0
即x²+y²)(x-y)<(x²-y²)(x+y)
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