先化简再求值,(x+y)^2+2(x^2-y^2)+(x-y)^2,其中x=3,y=1/3_数学解答

先化简再求值,(x+y)^2+2(x^2-y^2)+(x-y)^2,其中x=3,y=1/3

人气：440 ℃　时间：2020-09-22 00:38:14

解答

(x+y)^2+2(x^2-y^2)+(x-y)^2
=(x+y)^2+2(x-y)(x+y)+(x-y)^2
=(x+y+x-y)^2
=4x^2
=4×3^2
=36