### Options

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

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 $$\cos(\theta)=x$$.
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 $$\theta$$.