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May 24th, 2007, 11:48 PM  #1 
Newbie Joined: May 2007 Posts: 1 Thanks: 0  Help with circle and tangent point?
I'm having trouble with a problem. A quick response would be appreciated. They give me a circle on a x and y axis, but with no graph lines. The circle is not in the center. They give me a tangent point, and ask for the equation of the tangent line. How do I find it? 
May 25th, 2007, 02:43 AM  #2 
Senior Member Joined: Nov 2006 From: I'm a figment of my own imagination :? Posts: 848 Thanks: 0 
If you know the center of the circle, find the slope of the line to the tangent point. If that slope is m, then the tangent line will have slope 1/m. From there, you can simply give the equation of the line in pointslope form, and convert it to slope intercept form.

May 25th, 2007, 09:59 AM  #3 
Senior Member Joined: Dec 2006 Posts: 1,111 Thanks: 0 
Do you have a clue where the center of the circle is? You can easily enough find the equation of any line tangent to any circle as long as you know where the center of the circle is. Can you deduce the coordinates of the center from any other data they give you?


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