View Full Version : The equation of a diameter of a circle passing through the origin is x + why = 1 and th
 
 lee1111
Mar 6, 2011, 12:51 AM
The equation of a diameter of a circle passing through the origin is x + y = 1 and th
 
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the equation of diameter of a circle passing through the origin is x y=1 and the greatest distance of any point of the circle from the diameter is (5)^1/2.then the equation of the circle is?
 galactus
Mar 6, 2011, 10:15 AM
Didn't you preview your problem before posting? It appears to be cut off? 
 
Do you need the equation of a circle whose diameter is the line x+y=1? 
 
There could be many circles with radius on this line, but say you want one that passes through 
(1,0) and (0,1).
 
The line y=-x+1 crosses the x-axis at (1,0) and the y-axis at (0,1).
 
The distance between these two points is then \sqrt{2}
 
This is the length of the circles diameter. Thus, the radius is \frac{\sqrt{2}}{2}
 
By using the midpoint formula, we find the circle has center (\frac{1}{2}, \;\ \frac{1}{2})
 
Now, there's the center and radius, write out the equation.
 
(x-\frac{1}{2})^{2}+(y-\frac{1}{2})^{2}=(\frac{\sqrt{2}}{2})^{2}
 Unknown008
Mar 7, 2011, 08:58 AM
The general equation of a circle is:
 
(x - a)^2 + (y - b)^2 = r^2
 
where (a, b) is the coordinates of the centre of the circle and r is the radius of the circle.
 
As you can see, this is similar to the equation that galactus posted above, but with a = 1/2, b = 1/2 and r = \sqrt{2}/2.
 
Can you give your problem a try?
 lee1111
Mar 8, 2011, 11:21 AM
I tried to solve the problem but I am not getting the correct answer... :(
Its given that greatest distance of any point of the circle from the diameter is root 5
 Unknown008
Mar 8, 2011, 12:26 PM
What answer did you come to?