问题标题:
【高一数学方程综合请详细解答,谢谢!(1217:26:9)正数x,y满足x2-y2=2xy   求  (x-y)(x+y)】
问题描述:

高一数学方程综合请详细解答,谢谢!(1217:26:9)

正数x,y满足x2-y2=2xy   求  (x-y)(x+y)

刘鹰回答:
  正数x、y满足正数x、y满足x2-y2=2xy,   x2-y2=2xy   x2-2xy+y2-2y2=0   (x-y)2=2y2   x-y=√2*y   x=(√2+1)y   (x—y)/(xy)==√2*y/(√2+2)y   =√2/(√2+2)   =√2(2-√2)/(4-2)   =√2-1
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