当椭圆的焦点为x轴上时:设椭圆的标准方程为(x²/a²)+(y²/b²)=1(a>b>0)则,(4/a²)+(4/b²)=1且e=c/a=√2/2 ==> e²=c²/a²=1/2 ==> (a²-b²)/a²=1/2==> a²=2b²那么:(2/b²)+(4/b²)=1所以,b²=6则,a²=12所以,椭圆的标准方程为:(x²/12)+(y²/6)=1当椭圆焦点在y轴上时,标准方程为:(x²/6)+(y²/12)=1