A geometric argument for the limit of sin(x)/x as x --> 0
Drag the point C along the unit circle. Here X measures the angle in radians.
Observe how sin X (length of the blue dotted line), X (length of the arc), and tan X (length of the red line) change as X approaches 0.
Using the squeeze theorem, present an argument that sin(X)/X approaches 1 as X approaches 0.