SOLUTION: Consider the elipse 9x^2 + 36y^2=324. Which of the following statements about the foci and eccentricity is correct? A) the foci are [(0,-3(square root of 3)] and [(0,3(squar

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Consider the elipse 9x^2 + 36y^2=324. Which of the following statements about the foci and eccentricity is correct? A) the foci are [(0,-3(square root of 3)] and [(0,3(squar      Log On


   

Question 1198938: Consider the elipse 9x^2 + 36y^2=324.
Which of the following statements about the foci and eccentricity is correct?
A) the foci are [(0,-3(square root of 3)] and [(0,3(square root of 3)], and the eccentricity is (1/2)(square root of 3)
B) the foci are [(0,-3(square root of 3)] and [(0,3(square root of 3)], and the eccentricity is square root of 3
C) the foci are [(-3(square root of 3), 0] and [(3(square root of 3),0], and the eccentricity is (1/2)(square root of 3)
the foci are [(0,-3(square root of 3)] and [(0,3(square root of 3)], and the eccentricity is (1/2)(square root of 3)
D) the foci are [(-3,(square root of 3),0] and [(3(square root of 3),0], and the eccentricity is square root of 3
Found 2 solutions by Edwin McCravy, mccravyedwin:
Answer by Edwin McCravy(20056) About Me  (Show Source):
Answer by mccravyedwin(407) About Me  (Show Source):
You can put this solution on YOUR website!
Get the equation in standard form with the center as the center: 

x%5E2%2Fa%5E2%2By%5E2%2Fb%5E2=1 if a > b or x%5E2%2Fb%5E2%2By%5E2%2Fa%5E2=1 if a < b



So a2 = __, and a = __,
   b2 = __, and b = __

For all ellipses, eccentricity=e=+c%2Fa where c%5E2=a%5E2-b%5E2



The foci are + or - c units left and right from the center (the origin).

The foci are (__,__) and (__,__).

For the eccentricity:



Edwin