Cosine Function (COS)

COS(expr)

Function Description

The cosine function COS is used to calculate the cosine value of a given angle (parameter expr). This function is widely used in fields such as mathematics, physics, and engineering, especially when solving problems related to periodic changes.

Parameter Description

• expr (type double): The angle for which the cosine value needs to be calculated, in radians. If the input angle is in degrees, it needs to be converted to radians first. Degrees can be converted to radians by multiplying by π/180.

Return Result

Returns the cosine value of the parameter expr, with the result type being double.

Usage Example

1. Calculate the cosine value of 0 radians:

SELECT COS(0);
// Result: 1.0

2. Calculate the cosine of 90 degrees (π/2 radians):

SELECT COS(PI()/2);
// Result: 0

3. Calculate the cosine of 180 degrees (π radians):

SELECT COS(PI());
// Result: -1

4. Calculate the cosine value of 270 degrees (3π/2 radians):

SELECT COS(3*PI()/2);
// Result: 0

5. Calculate the cosine value of a negative angle (-π/4 radians):

SELECT COS(-PI()/4);
// Result: approximately 0.7071

Through the above example, you can understand how to use the cosine function COS to calculate the cosine values of different angles. In practical applications, you can calculate the cosine values of any angle as needed to solve various problems related to periodic changes.