This article focus to Define and Discuss on Trigonometric Functions. In trigonometry, angle measure is expressed in 1 of 2 units: degrees or radians. The relation between these measures can be expressed as follows: 180° = π radians. To vary degrees to radians, same relationship 1° = π/180 radians is used, and the given volume of degrees is multiplied by π/180 to convert to be able to radian measure. Similarly, the equation 1 radian = 180°/π is used to change radians to be able to degrees by multiplying the actual given radian measure by 180/π to obtain the degree measure.