SOLUTION: Find the foci for each equation. 1) 4x^2 + 9y^2 = 36 2) 36x^2 + 4y^2 = 144 3) 36x^2 + 8y^2 = 288

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Find the foci for each equation. 1) 4x^2 + 9y^2 = 36 2) 36x^2 + 4y^2 = 144 3) 36x^2 + 8y^2 = 288      Log On


   

Question 427971: Find the foci for each equation.
1) 4x^2 + 9y^2 = 36
2) 36x^2 + 4y^2 = 144
3) 36x^2 + 8y^2 = 288
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
1) x%5E2%2F9+%2B+y%5E2%2F4+=+1 ==> a = 3, b = 2 ==> c = sqrt%28a%5E2+-+b%5E2%29=+sqrt%289+-+4%29+=+sqrt%285%29 ==> the foci are (sqrt%285%29, 0) and (-sqrt%285%29, 0).
2) x%5E2%2F4+%2B+y%5E2%2F36+=+1 ==> a = 6, b = 2 ==> c = sqrt%28a%5E2+-+b%5E2%29=+sqrt%2836+-+4%29+=+sqrt%2832%29+=+4sqrt%282%29 ==> the foci are (0, 4sqrt%282%29) and (0, -4sqrt%282%29).