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.
![\text{cos}\sec \text{(}\theta)\text{ = }(1)/(\sin (\theta))=(1)/(0)\text{ = undefined}]()
The sec is the inverse of the cossine.
