Question 678416:  Find the equation of the circle if it is tangent to the line x+y=2 at point (4,-2) and the center at x-axis. 
 Answer by MathLover1(20850)      (Show Source): 
You can  put this solution on YOUR website!  
 
 
(h,k)-center and r radius
 
given:
 
given:
 
 the circle if it is tangent to the line   at point ( , ) and the center at  
 
 
find the equation of the circle:
 
Let ... C( , ) be the center.
 
Also, let the line L :  touch
 
this circle at the point A( , )
 
Line     has slope  
 
and slope of seg AC is  .
 
Since line L is perpendicular to segment AC,  
 
 
 
 
 
 
 
 
 
 
 
Hence, C ≡ ( , ) ≡ ( , )
 
and 
 
 .
 
Hence, by Center-Radius Form, eq of circle is:
 
 
 
 
 
 
 ......... your answer
 
 
 
 
  
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