已知x2+y2-4x-2y+5=0,求log(x)y^x的值.
x^2-4x+4+y^2-2y+1=0
(x-2)^2+(y-1)^2=0
x-2=0 y-1=0
x=2 y=1
log(x)y^x=log(2)1^2=log(2)1=0