x^2y+xy^2 =xy(x+y) = 1/5
(x^2+1)(y^2+1)
= (xy)^2 + x^2 + y^2 +1
= (xy)^2 + (x+y)^2 - 2xy + 1
= 1/25 + 1 - 2/5 + 1
= 41/25（X的平方+1)（Y的平方+1） 呢得41／25啊。。。。。。第二个就是了