Question

here, I DONT GET CIRCLES, whats a tangent on a circle?

Answer 1

Your mean a tangent line? If so its just a line that touches the circle at one point.

Answer 2

a tangent line to a circle is a line that touches ONLY ONE point on that circle

Answer 3

a circle is not a function and its most basic equation is something like \[x ^{2} + y ^{2} = r ^{2}\]