posted by Chelsea .
Find an expression for the function whose graph is the given curve.
The top half of the circle x^2 + (y-2)^2 = 4
My final answer is y= 2 +/- sqrt of x-4
However, I circled the positive sign because that's the top half. Is this right? I was not sure whether it was sqrt of x-4 or sqrt of x^2-4
you are solving for y, so ...
(y-2)^2 = 4 - x^2
y - 2 = ± √(4-x^2)
since you want the top part
y = + √(4-x^2) + 2
incidentally, √(4-x^2) ≠ 2-x
e.g. √(16 - 4) = √12 ≠ 4-2