5x的平方+9y的平方=100x²/20+y²/(100/9)=1a²=20b²=100/9c²=20-100/9=80/9所以离心率e=c/a=√(80/9)/20=(2√5)/3焦点坐标((4/3)√5,0)(-4/3√5,0)顶点坐标(2√5,0)(-2√5,0)(0,10/3)(0,-10/...