Um . . . with a pencil and a ruler?
Very funny, Soroban.
A secant line is one that intersects the curve at two points. It's often used to approximate a tangent line, which only touches the curve at one point.
To be technically correct, we're only considering a small range of x values - of course it's possible for the curve to turn around and intersect the line at any number of points.
- Hollywood