COS() function

SELECT COS( X )

COS() with PI()

SELECT COS(PI()); // Ouput is -1
SELECT ROUND(COS(PI()/2),2); // Ouput is 0.00
SELECT ROUND(COS(PI()/3),2); // Ouput is 0.5 

COS() with RADIANS

Radians function convert degree value to radian.

SELECT COS(RADIANS(0)); // Ouput is 1
SELECT ROUND(COS(RADIANS(90)),2); // Output is 0.00
SELECT COS(RADIANS(180)); // Output is -1