The cotangent of a number is given by:
Since the value of the cotangent is undefined, the value of the sine must be equal to 0. Thefore:
We know that when the sine of an angle is equal to 0, its cosine is equal to 1 or -1. Since the interval is from pi/2 to 3pi/2. Thefore:
The tangent is the division between the sine and cosine.
The cossec is the inverse of the sine.
The sec is the inverse of the cossine.