若xy互为倒数,则x的²-(1/y)²=?

若xy互为倒数,则x的²-(1/y)²=?
若xy互为倒数,则x的²-(1/y)²=?

若xy互为倒数,则x的²-(1/y)²=?
xy互为倒数
∴x=1/y
x的²-(1/y)²=(1/y)²-(1/y)²=0

即1/y=x
所以原式=x²-x²=0

xy互为倒数,则x=1/y切xy都不等于0
x²-(1/y)²=(1/y)²-(1/y)²=0

x²-(1/y)²=(x+1/y)(x-1/y)=(xy+1)/y*(xy-1)/y=0 , (xy=1)