The range of angles is limited by the definition of diagonal in mathematics. In mathematics, an angle is the vertex of a plane figure formed by two intersecting lines. When the angle exceeds 360 degrees, we can subtract 360 degrees from it to get the angle within the range.

In trigonometric function problems, basic relations are usually used to solve problems. Basic relations refer to the basic properties of trigonometric functions, including sin a=a/c, cos a=b/c, tan a=a/b, and the basic relations of inverse trigonometric functions. Using basic relations can make it easier to solve problems.

However, in practical application, it is not necessary to use basic relations to solve problems every time. In some cases, the correct answer can also be obtained by using other methods or formulas.