# What is cotangent?

In most cases, students and their parents have a lot of questions about the subject of trigonometry. In trigonometry, children learn what the sines are cosines, tangents, and cotangents. Unfortunately, not even all adults know how all these trigonometric concepts differ from each other. We will completely devote this article to the cotangents, first of all, we will learn what the cotangent is and why it is needed.

Cotangent is a trigonometric function, which is always referred to as "ctg". If you consider the cotangent of an acute angle in such a figure as a right-angled triangle, then remember, in this case it will always be equal to the ratio of the leg that goes from this angle to the leg that is opposite to it. If you are interested in the value of cotangent for the most common angles, then the following information will be useful for you:

- ctg angle of 30 degrees is equal to the root of 3;
- ctg angle of 45 degrees is 1;
- ctg angle of 60 degrees is 1 / root of 3 (one divided by the root of three);
- The ctg angle of 90 degrees and the ctg angle of 270 degrees are 0.