Question 194144
find the foci of this ellipse? 
x^2+9y^2=1
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Put the equation in standard form:
[x^2/1] + [y^2/(1/9)] = 1
The center is at (0,0)
The foci are at (-c,0), (c.0)
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Then a = 1  and b = 1/3
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For an ellipse a^2 = b^2 + c^2
So c^2 = 1^2 - (1/3)^2 = 8/9
Then c = (2/3)sqrt(2)
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Foci are at ((-2/3)sqrt(2)),0) and ((2/3)sqrt(2),0)
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Cheers,
Stan H.