SOLUTION: identify the foci,of the following ellipse. sketch each. 1. (x-1)^2/25 + (y+2)^2/16 = 1

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Question 430947: identify the foci,of the following ellipse. sketch each.
1. (x-1)^2/25 + (y+2)^2/16 = 1

Found 2 solutions by ewatrrr, Gogonati:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi
Standard Form of an Equation of an Ellipse is %28x-h%29%5E2%2Fa%5E2+%2B+%28y-k%29%5E2%2Fb%5E2+=+1+
where Pt(h,k) is the center and a and b are the respective vertices distances from center.
(x-1)^2/25 + (y+2)^2/16 = 1 | a = 5 and b = 4 C(1,-2)
f = sqrt(25-16) = 3 (foci are located 3 each side of center along major axis)
|foci are (-2,-2) and (4,-2)


Answer by Gogonati(855) About Me  (Show Source):
You can put this solution on YOUR website!
Solution: The center of this ellipse is the point (1, -2), a^2=25 and b^2=16
As we know c^2=a^2-b^2=25-16=9, thus, c%5E2=9, And c=/- sqrt(9)
c=-3 and c=3, hence the coordinates of the foci will be:(-3,0) and (3,0),when the ellipse was centered at (0, 0), Our ellipse was shifted at poit (1, -2), thus the new foci will be:(-3+1, 0-2) and (3+1, 0-2), simplify: (-2, -2) and (4, -2).
Answer: the foci of ellipse are: (-2, -2) and (4, -2)

Done.