👉 In mathematics, "arctogaean" is a term used to describe an angle whose cosine is equal to its tangent. This describes angles in which the sine and cosine of the angle are both rational numbers. An example of this type of angle can be found in trigonometry, particularly with right triangles. In such cases, if we have a right triangle where one side (the hypotenuse) is 1 unit long, and the other two sides are measured as being equal to \