1, sin? α+cos？ α= 1

2. 1+ Tan? α = seconds? α

3、 1+cot？ α=csc？ α

4. sin? α=( 1-cos2a)/2

5、cos？ a=( 1+cos2a)/2

6. Tan? a=(2tana- 1)/(tan2a)

The trigonometric function of extended data is a function that belongs to the transcendental function in elementary function in mathematics. Their essence is the mapping between any set of angles and a set of ratio variables. The usual trigonometric function is defined in a plane rectangular coordinate system. Its definition field is the whole real number field. The other is defined in a right triangle, but it is incomplete.

Functional relationship:

Reciprocal relationship: ①; ②; ③?

Business relationship: ①; ②.

Square relation: ①; ②; ③?

References:

Baidu Encyclopedia-formulas of trigonometric functions