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#1 2006-09-11 04:59:02

runlemmingsrun1
Guest

Please help:ALGEBRA

Describe the graph of following equation:

(X-1)2 +(Y-8)2=16

#2 2006-09-11 05:25:48

Dross
Member
Registered: 2006-08-24
Posts: 325

Re: Please help:ALGEBRA

runlemmingsrun1 wrote:

Describe the graph of following equation:

(X-1)2 +(Y-8)2=16

First, you have to re-arrange your equation into the form y = mx + c, where m and c are numbers to be found. Do this as follows:



(X - 1)2 + (Y - 8)2 = 16

2X - 2 + 2Y - 16 = 16

2Y = -2X + 34

Y = -X + 17



So we've found that m = -1 and c = 17. When an equation is written in the form y = mx + c, the number m corresponds to the slope of the graph, and the number c corresponds to the point that the graph intercepts the y-axis at.
So, for this equation, it crosses the y-axis at y = 17 and has a slope of gradient -1.
Hope this is clear.


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#3 2006-09-11 05:45:41

runlemmingsrun1
Guest

Re: Please help:ALGEBRA

Thanks Drosse for a quick reply.I'm really occupied at the moment but need to submit assignments soon as well.

The problem is that the equation had a square in it instead of multiply by 2. I just didnt know how to put it to square 2.So please can you solve it for a power of 2.

Thanks

#4 2006-09-11 05:54:01

Dross
Member
Registered: 2006-08-24
Posts: 325

Re: Please help:ALGEBRA

Ah, so it was:

In this case, the quation of a circle about the origin with radius

is
. The equation you've given has a very similar form, except that
and
. What this means is that whatever graph is being described is similar to one with a form
, but it has been shifted along the x-axis by one unit and along the y-axis by 8 units (both in the positive directions).

So your equation is the equation of a circle of radius 4 with it's center at (1,8).


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#5 2006-09-11 06:06:15

runlemmingsrun1
Guest

Re: Please help:ALGEBRA

Thanks .If the equation was

(X+2)2 + (Y-4)2=36


It has been shifted to X-axis by 4 units and Y-axis by 16 units and has a radius of 6.

Am I right??

Thanks

#6 2006-09-11 11:06:53

Dross
Member
Registered: 2006-08-24
Posts: 325

Re: Please help:ALGEBRA

runlemmingsrun1 wrote:

Thanks .If the equation was

(X+2)2 + (Y-4)2=36


It has been shifted to X-axis by 4 units and Y-axis by 16 units and has a radius of 6.

Am I right??

Thanks


You are correct in that the circle in this question does have a radius of 6, since
.

What you seem to be doing is squaring the distances that the circle has been moved by - you don't need to do this at all. It has been moved along the x-axis by 2 units and along the y-axis by 4 units.

Also, remember that it has been moved along the x-axis in the negative x-direction, and along the y-axis in the positive y-direction, so the center of the circle will be at the point (-2,4).


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#7 2006-09-17 07:53:48

coolcat23
Member
Registered: 2006-06-21
Posts: 553

Re: Please help:ALGEBRA

I don't mean to be rude but that seems really hard.


The world revolves around me. Deal with it. cool

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#8 2006-09-17 11:48:30

runlemmingsrun1
Guest

Re: Please help:ALGEBRA

It is just one of those things. this is it, and I have got to get on with it...
Hope this makes sense and have a great weekend...

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