1. The A.B.C of the ellipse is known to be an equal ratio sequence, and the eccentricity is calculated 2. If the endpoint of the minor axis of the ellipse and the two focal points form an isosceles right triangle, calculate the eccentricity

1. The A.B.C of the ellipse is known to be an equal ratio sequence, and the eccentricity is calculated 2. If the endpoint of the minor axis of the ellipse and the two focal points form an isosceles right triangle, calculate the eccentricity

1、b²=ac
a²=b²+c²
∴a²=c²+ac
Let a = 1, C = (radical 5-1) / 2
So the centrifugal ratio is C / a = (radical 5-1) / 2
2. Let the focal length be 2, that is, C = 1
Then the length of semi minor axis = b = C = 1
So a = radical (1 + 1) = radical 2
So the centrifugal ratio is C / a = (radical 2) / 2