Engineering Board Exam Reviewer · Ellipses · easy

Find the foci of the ellipse x2/25+y2/9=1.

  1. ( 5,0)
  2. (0, 4)
  3. ( 3,0)
  4. ( 4,0)

Answer

D. ( 4,0)

Solution

c2=a2-b2=25-9=16 c=4. The major axis is horizontal, so the foci are ( 4,0).

More Ellipses questions

  1. Find the length of the major axis of the ellipse x2/25+y2/9=1.
  2. Find the distance from the center of the ellipse x2/25+y2/9=1 to each directrix.
  3. Find the area of the largest rectangle that can be inscribed in the ellipse x2/25+y2/9=1.
  4. Find the distance between the foci of the ellipse 4x2+9y2-16x+18y-11=0.
  5. Find the equation of the ellipse with center at the origin, vertices at ( 6,0) and a minor axis of length 8.
  6. A point on the ellipse 4x2+9y2=36 has x=2 and y>0. Find its y-coordinate.
  7. The major axis of an ellipse is twice its minor axis. Find the eccentricity.
  8. Find the area enclosed by the ellipse x2/16+y2/9=1.
  9. For any point on the ellipse 9x2+25y2=225, find the sum of its distances from the two foci.
  10. Find the foci of the ellipse (x-2)2/25+(y+1)2/9=1.

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