[(a^-2)-(b^-2)]÷[(a^-1)-(b^-1)][(x^-2)(y^-2)]÷[(x^-1)-(y^-2)]注:/为分数线

问题描述:

[(a^-2)-(b^-2)]÷[(a^-1)-(b^-1)]
[(x^-2)(y^-2)]÷[(x^-1)-(y^-2)]
注:/为分数线

(1)
[(a^-2)-(b^-2)]÷[(a^-1)-(b^-1)]={[(a^-1)-1]-[(b^-1)-1]}/[(a^-1)-(b^-1)]=
[(a^-1)-(b^-1)]÷[(a^-1)-(b^-1)]=1