NIMCET 2011 — Mathematics PYQ
NIMCET | Mathematics | 2011The eccentricity of ellipse 9x2+5y2−30y=0 is:
Choose the correct answer:
- A.
1/3
- B.
2/3
(Correct Answer) - C.
3/4
- D.
1/4
2/3
Explanation
1. Complete the Square for the y-terms:
The given equation is:
To complete the square inside the parentheses, add (2−6)2=9:
2. Convert to Standard Form:
Divide the entire equation by 45:
3. Identify Semi-axes:
Comparing with a2x2+b2(y−k)2=1:
-
a2=5
-
b2=9
Since b^2 > a^2, this is a vertical ellipse.
4. Calculate Eccentricity (e):
For an ellipse where b > a, the eccentricity is given by the formula:
Substitute the values:
Correct Option: (b)
Explanation
1. Complete the Square for the y-terms:
The given equation is:
To complete the square inside the parentheses, add (2−6)2=9:
2. Convert to Standard Form:
Divide the entire equation by 45:
3. Identify Semi-axes:
Comparing with a2x2+b2(y−k)2=1:
-
a2=5
-
b2=9
Since b^2 > a^2, this is a vertical ellipse.
4. Calculate Eccentricity (e):
For an ellipse where b > a, the eccentricity is given by the formula:
Substitute the values:
Correct Option: (b)
