1.方程可化为:[x-(t+3)]^2+[y+(1-4t^2)]^2=(t+3)^2+(1-4t^2)^2-(16t^4+9)
因为该方程表示圆,故(t+3)^2+(1-4t^2)^2-(16t^4+9)>0
不等式化简得-7t^2+6t+1>0,即7t^2-6t-1
1.方程可化为:[x-(t+3)]^2+[y+(1-4t^2)]^2=(t+3)^2+(1-4t^2)^2-(16t^4+9)
因为该方程表示圆,故(t+3)^2+(1-4t^2)^2-(16t^4+9)>0
不等式化简得-7t^2+6t+1>0,即7t^2-6t-1