## Circle equation

Complex numbers, rational functions, logarithms, sequences and series, matrix operations, etc.
rogermiranda00
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Joined: Wed Mar 19, 2014 12:57 pm
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### Circle equation

I have to write a polynomial equation based on this info.
Then tell what conic the equation describes.

The distance from a point (x,y) to a fixed point (-3,0) is twice the distance form the point to another fixed point (3,0).

Here is what I did.

The distance from (x,y) to (-3,0) is d1
The distance from (x,y) to (3,0) is d2
d1 = 2* d2
Using the distance formula and doing the algebra I get x^2 - 30x + 3y^2 = 0.
The correct answer is x^2 + y^2 - 10x + 9 = 0 which is a circle.

Can someone please give me a hint for this. thanks.

stapel_eliz
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Using the distance formula and doing the algebra I get x^2 - 30x + 3y^2 = 0.
Please reply showing these steps, so any errors can be located and corrected. Thank you!

rogermiranda00
Posts: 2
Joined: Wed Mar 19, 2014 12:57 pm
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### Re: Circle equation

Thanks! I reworked the problem and got the right answer! I found my own mistake.