lovely353
幼苗
共回答了13个问题采纳率:100% 举报
1.x^2/16+y^2/4=1
a=4,b=2,c=2*3^(1/2)
e=c/a=[3^(1/2)]/2,
焦点:(2*3^(1/2),0),(-2*3^(1/2),0)
顶点坐标:(4,0),(-4,0),(0,2),(0,-2)
2.x^2/9+y^2/81=0
a=9,b=3,c=6*2^(1/2)
e=c/a=[2*2^(1/2)]/3
焦点:(0,6*2^(1/2)),:(0,-6*2^(1/2))
顶点:(3,0),(-3,0),(0,9),(0,-9)
1年前
2