Posted by alk on Friday, July 18, 2008 at 1:03pm.
For the circle x^2+y^2+6x4y+3=0
how would i go about finding:
a) the center and the radius
b) the equation of the tangent line at the point (2,5)
any help is mch appreciated. thanks!

math  drwls, Friday, July 18, 2008 at 3:20pm
(a) Rewrite the equation as
x^2 + 6x + 9 + y^2 4y + 4 +3 13 = 0
(x+3)^2 + (y2)^2 = 10 = (sqrt 10)^2
The should tell you that the center is at (3, 2) and the circle radius is sqrt 10.
(b) First cmpute the slope dy/dx at (2, 5)using implicit differentiation.
2x + 2y y' + 6 4 y'= 0
y'(4  2y) = 2x + 6
y' = 2/(42y) = 1/3
Finally, write down the equation of s straight line passing through (2,5) with that slope.
Verify my numbers. I may have goofed somewhere along the line
Answer This Question
Related Questions
 calc  standard equation of circle concentric with X^2+Y^22X8Y+1=0 and tangent...
 Math (Pre Cal)  Hi, I am studying for a precalculus quiz and I do not ...
 math  a circle is tangent to the yaxis at y=3 and has one xintercept at x=1 a...
 Please Help! Math  How to find the center and radius of a circle using 3 points...
 math  From an exteror point P that is h units form a circle of radius r, a ...
 MATH  How do i find the center of a circle using 3 points. Also need to find ...
 Math (geometry)  Line l is tangent to circle O at point P(3,4) where the center...
 Math  I have a series of questions that I did. They lead up to the last ...
 Math  I have a question my brother asked me but I need a math expert. You have ...
 Alg2  The tangent to a circle may be defined as the line that intersects the ...
More Related Questions