Given a function f(x), and two points on the curve (a, f(a)) and (b, f(b)) the line joining these two points is called a secant line of f. (Not to be confused with the trigonometric secant (sec) ...
To find the tangent line to a curve at a point P we first pick another point on the curve a little bit away from P. Call this point Q. Do this below by clicking "Another Point". Then connect these two ...