Question 43230
<pre><font size = 4><b>Give the equation for the right half of the circle. C(2,3).
I plotted it out to x=2+squrt9-(y-3)^2.  Not sure about 
the signs if I have them right or not.  thanks for checking.

I will assume the radius is 3.  You forgot to give that.

The equation of the circle is

(x - 2)² + (y - 3)² = 3²

(x - 2)² + (y - 3)² = 9

Since you want the right half, 
solve for x.

(x - 2)² = 9 - (y - 3)²

Since you want the right half,
take positive square roots of
both sides:
            ____________
   x - 2 = <font face = "symbol">Ö</font>9 - (y - 3)² 
                ____________
       x = 2 + <font face = "symbol">Ö</font>9 - (y - 3)² 

Yes it looks like you're right.

{{{ graph( 200, 200, -12, 12, -12, 12, 3+sqrt(9-(x-2)^2)*sqrt(x-2)/sqrt(x-2), 3-sqrt(9-(x-2)^2)*sqrt(x-2)/sqrt(x-2) )}}}

Edwin</pre>