x+y-2（t+3）x+2（1-4t）y+16t^4+9=0 (x-(t+3))+(y+(1-4t))+16t^4+9=(t+3)+(1-4t) (x-(t+3))+(y+(1-4t))+16t^4+9=t+6t+9+1-8t+16t^4 (x-(t+3))+(y+(1-4t))=-7t+6t+1 半径必须大于0,所以 -7t+6t+1>0 7t-6t-1...