When it comes to knowing the meaning of the term cotangent, it is necessary, first, to discover what its etymological origin is. In this case, we can state that it is a word that derives from Latin. It is exactly the result of the union of three delimited components:
-The prefix "co-", which can be translated as "together".
-The verb "tangere", which means "to touch".
-The suffix "-nte", which is used to indicate "agent".

Starting from all that, we find the fact that cotangent means "inverse of the tangent of an arc or of an angle".
The notion of cotangent refers to the inverse tangent function of an arc or an angle. To understand what the cotangent is, therefore, we must know what the tangent .
In the context of the trigonometry (a specialty of mathematics), the tangent of a right triangle is obtained dividing the opposite leg at an acute angle and the adjacent leg . It should be remembered that the major side of these triangles is called hypotenuse , while the other two receive the denomination of legs .
Returning to the idea of cotangent, we had already mentioned that it is the inverse function of the tangent. Therefore, if the tangent is the quotient between the opposite leg and the adjacent leg, the cotangent equivalent to quotient between the adjacent leg and the opposite leg .
In a right triangle whose hypotenuse measures 20 centimeters, its adjacent leg measures 15 centimeters and its opposite leg measures 12 centimeters, we can calculate the cotangent as follows:
Cotangent = Adjacent leg / Opposite leg
Cotangent = 15/12
Cotangent = 1.25
Since the cotangent is the inverse function of the tangent, it can also be obtained dividing 1 by the tangent . In our example above, the tangent equals 0.8 (the result of the division between the opposite leg and the adjacent leg). Thus:
Cotangent = 1 / Tangent
Cotangent = 1 / 0.8
Cotangent = 1.25
Within the field of mathematics, and more specifically in the field of trigonometry, the cotangent plays an important role. Specifically, we talk about what are the properties of the cotangent function. And these are none other than continuity, dominance, travel, decreasing or period, for example.
Just as the cotangent is the inverse function of the tangent, the cosecant is the inverse of breast and the drying , the inverse of cosine .
In the same way, we cannot ignore the existence of what is known as hyperbolic cotangent. This is another term used in trigonometry in relation to a real number. In that case it is established that it becomes the inverse of the hyperbolic tangent.
It is represented by coth (x) or through cotgh (x) and on that same there is what is called the addition theorem. A theorem that comes to expose the way to synthesize this cited hyperbolic tangent.