21.5-3根号3
1所以a=1y=1/2-根3=-(根3-1/2)而0<根3-1/2<1所以b=05a^2+(x-b)^2-y^2=5+(1/2+根3)^2-(根3-1/2)^2=5-1/12+2根3=59/12+2根3
