已知x+y=2,xy=0.5,求x2+y2与(x-y)2的值
问题描述：
已知x+y=2,xy=0.5,求x2+y2与(x-y)2的值
答
x2+y2=x²+2xy+y²-2xy=(x+y)²-2xy=4-1=3
(x-y)2=x²-2xy+y²=x²+2xy+y²-4xy=(x+y)²-4xy=4-2=2
答
x^2+y^2
=(x+y)^2-2xy
=4-2*0.5
=3
(x-y)^2
=x^2+y^2-2xy
=(x+y)^2-4xy
=4-4*0.5
=2
答
x²+y²=(x²+2xy+y²)-2xy=(x+y)²-2xy=2²-2×0.5=4-1=3(x-y)²=x²-2xy+y²=(x²+2xy+y²)-4xy=(x+y)²-4xy=2²-4×0.5=4-2=2很高兴为您解答,【the 1990】...