实数a.b满足a²+2b²-2a+8b+9=0,试求a.b的值
问题描述:
实数a.b满足a²+2b²-2a+8b+9=0,试求a.b的值
答
a=1 b=-2
because(a-1)2+(b+2)2=0
答
a²+2b²-2a+8b+9=0
(a²-2a+1)+2(b²+4b+4)=0
(a-1)²+2(b+2)²=0
a-1=0 a=1
b+2=0 b=-2