当t属于R时,参数方程x=(-8t)/(4+t^2),y=(4-t^2)/(4+t^2)表示的图形是____
问题描述：
当t属于R时,参数方程x=(-8t)/(4+t^2),y=(4-t^2)/(4+t^2)表示的图形是____
答
x²=(64t²)/(4+t²)²y²=(4-t²)²/(4+t²)²=(t^4-8t^2+16)/(4+t²)²=(t^4+8t^2+16)/(4+t²)²-(16t^2)/(4+t²)²=1-x²/4故x²/4+y²...