数学问题，帮帮忙

如右图排数，请问第100行的第10个数是多少?                                                                                                                                      1                                                                                                                                                                                               2                 3                                                                                                                                                                               4              5           6                                                                                                                                                                     7            8           9          10                                                                                                                                                           。。。。。。                                                                                                                                                                                                                            收起

x^2+y^2-2(t+3)x+2(1-4t)y+16t^2+9=0? ? ?--->(x-t-2)^2+(y-1+4t^2)=(t+3)^2+(1-4t)^2-16t^2-9--->[x-(t+2)]^2+[y-(1-4t^2)]^2=t^2-2t+11)为使方程表示一个圆，应有t^2-2t+1>0--->(t-1)^2>0--->t<>12)由于r=(t-1)^2>0,所以半径r是任意正实数 收起

已知方程X^2+Y^2-2(T+3)X+2(1-4X^2)Y+16T^2+9=0表示一个圆求(1)T的取值范围(2)该圆的半径r的取值范围2(1-4X^2)Y到底是什么？？？如果是2(1-4T)Y，解法如下:已知方程:x^2+y^2-2(T+3)x+2(1-4T)y+16T^2+9=0表示一个圆。求(1)T的取值范围，(2)该圆的半径r的取值范围.解 配方如下:(x-T-3)^2+(y+1-4T)^2=(T-1)^2那么︱T︱>1。半径r>0. 收起