Show Radian angle multiples of:     π/2     π/4     π/3     π/6     Hide All    
Display:     Graphs of Sine & Cosine     Right Triangle and Trig Values

About the Unit Circle

The unit circle is the circle with radius one centered at the origin. The equation of this circle is \(x^2+y^2=1\). If the terminal edge of an angle \(\theta\) intersects the unit circle at the point \((x,y)\), then \(\sin(\theta) = y\) and \(\cos(\theta)=x\).

Using the Applet

This applet can be used to visualize the values of the trigonometric functions at particular angles, either by seeing the equivalent points on the graphs of \(\sin(\theta)\) and \(\cos(\theta)\), or by drawing a right triangle within the unit circle. After choosing which method you'd like to see, move your mouse over the circle to change the value of the angle \(\theta\).

About this Applet

This applet was created using JavaScript and the Raphael library. If you are unable to see the applet, make sure you have JavaScript enabled in your browser. This applet may not be supported by older browsers.