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#1 2011-03-26 13:25:51
- samuelbm
- Member
- Registered: 2011-03-26
- Posts: 6
ellipses
Hi! I'm trying to isolate the ''y'' in this equation: AY² + BXY + CY = 0
If there was no X, I would easily isolate in this form: A(Y+B)²=C and I'd just have to isolate the rest to finish.
Does someone can help me please?
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#2 2011-03-26 14:09:53
- soroban
- Member
- Registered: 2007-03-09
- Posts: 452
Re: ellipses
. . . .
.
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#3 2011-03-26 14:19:32
- samuelbm
- Member
- Registered: 2011-03-26
- Posts: 6
Re: ellipses
Hi, soroban!
We cannot consider y equal 0 that's my problem. Y and X are both variables. This is general a equation for drawing ellipses on my ti-83+ calculator program.
Thank you for trying 
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#4 2011-03-27 10:39:47
- samuelbm
- Member
- Registered: 2011-03-26
- Posts: 6
Re: ellipses
soroban, I thank about it and you're right by what I say. But what I should mentionned is we can't modified the right side or if we do we have to consider it is not equal to 0 but D.
AY² + BXY + CY = D
sorry, my bad
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#5 2011-03-27 13:03:35
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: ellipses
Hi samuelbm;
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#6 2011-03-27 15:13:19
- samuelbm
- Member
- Registered: 2011-03-26
- Posts: 6
Re: ellipses
Thank you very much bobbym!
I try to put numbers instead of variables and it do works!
But I still don't understand how you proceed to find it. I mean before posting this, I've checked everywhere on internet and it wasn't anything useful for me.
Congratulations, and thanks again!
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#7 2011-03-27 19:23:48
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: ellipses
Hi samuelbm;
You do it like this:
Notice it is just a quadratic in Y.
Now you just use the quadratic formula with a = A and b = (BX+C) and c = -D.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#8 2011-03-28 00:32:37
- samuelbm
- Member
- Registered: 2011-03-26
- Posts: 6
Re: ellipses
Ok thank you very much I got it
You save me hours of frustration
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#9 2011-03-28 00:47:13
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: ellipses
Hi samuelbm;
Your welcome.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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