In this animation we plot [math]y=\tan(x)[/math]. Here the unit on the [i]x[/i]-axis is degrees. There is no unit on the [i]y[/i]-axis. The [i]y[/i]-value of the tangent function for this angle is the [i]y[/i]-coordinate of the point T divided by the [i]x[/i]-coordinate of the point T.

Move the slider to α=60°. The [math]\tan(60^\circ) \approx 1.732[/math]. Do you know the exact value of [math]\tan(60^\circ)[/math]?[br]Move the slider to α=150°. The [math]\tan(150^\circ) \approx -0.577[/math]. Do you know the exact value of [math]\tan(150^\circ)[/math]?[br]Now, let α=–60°. Move the slider to the corresponding angle between 0° and 360°. The [math]\tan(–60^\circ)=\tan(300^\circ) \approx –1.732[/math]. Do you know the exact value of [math]\tan(–60^\circ)[/math]?[br]Does this agree with the fact that tan(–α)=–tan(α)?