$\"\"$

The circle equation is $\"x^2+(y-2)^2=4\"$ .

Find the top half of the circle.

Solve the equation for $\"y\"$ .

$\"x^2+(y-2)^2=4\"$

$\"(y-2)^2=4-x^2\"$

$\"y-2=\\pm$

The positive sign of the above function represents top half of the circle.

Hence, $\"y-2=+$

$\"y=2+$ .

$\"\"$

Top half of the circle is $\"f(x)=2+$ .