Solve by real function

Question

X^2+y^2=80

solve by real function

Answer 1

x^2 + y^2 = 80 is a circle with center (0,0) and radius sqr80=4sqr5 = about 8.8

general equation of a circle is

(x-h)^2 + (y-k)^2 = r^2 if (h,k) is (0,0), the center is the origin (0,0) if r^2=80, the radius = sqr80 = 4sqr5 = about 4(2.2) = 8.8

y^2 = 80-x^2

y = +sqr(80-x^2)

It's not a function, as they're 2 y values for each x value (except x=sqr80 or -sqr80)