Question

已知x-2y=0,求(x/y-y/x)乘xy/x^2-2xy+y^2

Answer 1

解

x-2y=0

x=2y

∴(x/y-y/x)×(xy/x²-2xy+y²)

=(2y/y-y/2y)×(2y²/4y²-4y²+y²)

=(2-1/2)×2

=4-1

=3