计算:(1/x-y-1/x+y)/2y/x^2-2xy+y^2,x=1+根号2,y=1-根号2
人气:452 ℃ 时间:2020-05-14 19:47:59
解答
[1/(x-y)-1/(x+y)]/[2y/(x^2-2xy+y^2)]={[(x+y)-(x-y)]/[(x+y)(x-y)]}*(x^2-2xy+y^2)/2y={2y/[(x+y)(x-y)]}*{(x-y)^2/2y}=(x-y)/(x+y)x=1+根号2,y=1-根号2,代入原式=【(1+根号2)-(1-根号2)】/【(1+根号2)+(1-根...
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