在二次根式的化简与求值中,(x~(1/2)+y~(1/2))与(x~(1/2)-y~(1/2))互为有理化因式,它们的乘积为x-y,在计算中像姐妹一样经常在一起,相互联系,使要解决的问题变得较为简单,可以称为“姐妹花”.在解决问题的过程中,如果能灵活地应用这个关系,可使我们的学习变得更有趣,更为直观. (X ~ (1/2) + y ~ (1/2)) and (x ~ (1/2) -y ~ (1/2)) are mutually exclusive in the quadratic root simplification and evaluation Physical and chemical factors, their product xy, in the calculation as often as sisters together, interrelated, so that the problem to be solved becomes more simple, can be called In the process of solving the problem, If we can flexibly apply this relationship, we can make our learning more fun and intuitive.