Points A and B are points on the curve. A is fixed, while B is not.[br]Start by moving B towards A (click on B and drag towards A), from both directions left and right. [br] [color=#c51414]What happens to the secant AB as B approaches A?[/color][br]Check both check boxes. Repeat the process.[br] [color=#c51414]What happens to the secant AB as B approaches A?[/color][br] [color=#c51414]What happens to [math]\Delta x[/math]? [math]\Delta y[/math]? The slope of the secant AB? Compare it to the slope of the tangent at A[/color]