(10)结论:D
圆(x-k/2)^2+(y-1)^2=(k^2/4)+(5k/4)+1
k满足条件:(k^2/4)+(5k/4)+1>0(成圆) 且(1-k/2)^2+(1-1)^2>(k^2/4)-(5k/4)+1(A在外)
解得-1