Common trigonometric functions in extended data include sine function, cosine function and tangent function. Other trigonometric functions, such as cotangent function, secant function, cotangent function, dyadic function, cofactor function, semidyadic function and semifactorial function, are also used in other disciplines, such as navigation, surveying and engineering.
In trigonometric functions, there are some special angles, such as 30, 45 and 60. The trigonometric function values of these angles are simple monomials, and the specific values can be obtained directly in the calculation.
References:
Baidu encyclopedia-trigonometric function