How do you find the domain and range of a circle?

1 Answer
Jul 13, 2018

#(x-a)^2+(y-b)^2=r^2

where the centre is (a,b) and the radius is r

The graph is a circle so all the points are enclosed in it

The domain is the values for x so you subtract the radius from the centre coordinate and you add the radius to it

The range is the values for y so you do the same to the y coordinate

If you use #(x+2)^2+(y-4)^2=25#

The centre is (-2,4) radius is 5

Domain #=> -2-5=-7#
and # -2+5=3#
[-7,3]

Range #=> 4-5=-1#
and #4+5=9#
[-1,9]