English: This animated diagram is an illustration of the unit-circle definitions of six trigonometric functions of angle θ, which vividly reflects the monotonicity of six trigonometric functions. In this image, the changes of the values of six trigonometric functions are reflected by the change of Cartesian coordinates of points A, B, C, D and E. The values of sin θ, tan θ and csc θ are represented by the ordinates of points A, B and D respectively, while the values of cos θ, cot θ and sec θ are represented by the abscissas of points A, C and E respectively.