若x+y=2,x^2+y^2=4,求:(1)xy的值,(2)x^3+y^3的值

问题描述:

若x+y=2,x^2+y^2=4,求:(1)xy的值,(2)x^3+y^3的值

(1)xy=0,(2)x^3+y^3=8过程是什么将式1两边平方后,与式2相减,得2xy=0,从而xy=0;则x=0,或y=0若x=0,y=2;反之,y=0,x=2.x^3+y^3=8