COMEDK2023Evening ShiftMathematicsEllipseActual
If the length of the major axis of an ellipse is 3 times the length of the minor axis, then its eccentricity is
Options
- A1 2
- B2 2 3
- C1 3
- D2 3
Correct answer
B. 2 2 3
Step-by-step solution
Let the length of the major axis be 2a and the length of the minor axis be 2b . Given that the length of the major axis is 3 times the length of the minor axis, we have 2a = 3(2b) , which simplifies to a = 3b . The eccentricity e of an ellipse is given by the formula e = 1 - b^2 a^2 . Substituting a = 3b into the formula: e = 1 - b^2 (3b)^2 e = 1 - b^2 9b^2 e = 1 - 1 9 e = 8 9 e = 8 3 = 2 2 3 Answer: 2 2 3