化简：(x-y)/(2x+1) * [(2x+1)/(x+y) - (2xy+y)/(y方－x方)]+y/(x+y)

化简：(x-y)/(2x+1) * [(2x+1)/(x+y) - (2xy+y)/(y方－x方)]+y/(x+y)
化简：(x-y)/(2x+1) * [(2x+1)/(x+y) - (2xy+y)/(y方－x方)]+y/(x+y)

化简：(x-y)/(2x+1) * [(2x+1)/(x+y) - (2xy+y)/(y方－x方)]+y/(x+y)
[(2x+1)/(x+y) - (2xy+y)/(y方－x方)]
=[(2x+1)(y-x)/(y^2-x^2) - y(2x+1)/(y^2-x^2)]
=(2x+1)(y-x-y)/(y^2-x^2)
=-x(2x+1)/(y^2-x^2)
(x-y)/(2x+1) * [(2x+1)/(x+y) - (2xy+y)/(y方－x方)]+y/(x+y)
=(x-y)/(2x+1) * [-x(2x+1)/(y^2-x^2)]+y/(x+y)
=(x-y)/(2x+1) * [x(2x+1)/(x-y)(x+y))]+y/(x+y)
=x/(x+y)+y/(x+y)
=1

：(x-y)/(2x+1) * [(2x+1)/(x+y) - (2xy+y)/(y方－x方)]+y/(x+y)
=(x-y)/(2x+1) * (2x+1)/(x+y)-(x-y)/(2x+1) * (2xy+y)/(y方－x方)+y/(x+y)
=(x-y)/(x+y)+y/（x+y)+y/（x+y）
=1