设圆心为(a,b)与x轴相切,则有r=|b|与x=-0.5相切,则有r=|a+0.5|即|b|=|a+0.5|而(a-1.5)^2+b^2=2,代入b,得：(a-1.5)^2+(a+0.5)^2=2a^2-a+0.25=0(a-0.5)^2=0a=0.5所以r=1,b=±1所以圆为(x-0.5)^2+(y±1)^2=1...