：（1/x-y-1/x+y)÷2y/x的平方+2xy+y的平方
=(x+y-x+y)/{(x-y)(x+y)}*(x^2+2xy+y^2)/2y
=(x+y)^2/(x-y)(x+y)
=(x+y)/(x-y)
带入
x+y=2√3
x-y=2√2
所以原式就等于2√3/2√2=(√6)/2
如有不明白,