SOLUTION: The major axis of an ellipse is 12 units and the foci are at (-4,-1)and (-4,7).Find the standard form of the equation of this ellipse,the length of minor axis ,the vertices and coo

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: The major axis of an ellipse is 12 units and the foci are at (-4,-1)and (-4,7).Find the standard form of the equation of this ellipse,the length of minor axis ,the vertices and coo      Log On


   



Question 671937: The major axis of an ellipse is 12 units and the foci are at (-4,-1)and (-4,7).Find the standard form of the equation of this ellipse,the length of minor axis ,the vertices and coordinates where the ellipse intercepts the minor axis.
Answer by lwsshak3(11628) About Me  (Show Source):
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The major axis of an ellipse is 12 units and the foci are at (-4,-1)and (-4,7).Find the standard form of the equation of this ellipse,the length of minor axis ,the vertices and coordinates where the ellipse intercepts the minor axis.
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This is an ellipse with vertical major axis.
Its standard form of equation: %28x-h%29%5E2%2Fb%5E2%2B%28y-k%29%5E2%2Fa%5E2=1, a>b, (h,k)=(x,y) coordinates of center
For given ellipse:
From given coordinates of foci
center: (-4,3)
given length of vertical major axis=12=2a
a=6
a^2=36
vertices: (-4,3±a)=(-4,3±6)=(-4,-3) and (-4,9)
c=4 (distance from center to foci)
c^2=16
c^2=a^2-b^2
b^2=a^2-c^2=36-16=20
b=√20≈4.47
length of minor axis=2b=2√20
where ellipse intercepts minor axis: (-4±b,3)=(-4±√20,3)=(-4-√20,3) and (-4+√20,3)
equation of given ellipse:
%28x%2B4%29%5E2%2F20%2B%28y-3%29%5E2%2F36=1