The COS function returns a cosine value of the argument. The argument x must be a radian value. The return value is a DOUBLE type.
COS( x )
SELECT COS(pi()/6), COS(pi()/3), COS(pi());
cos( pi()/6) cos( pi()/3) cos( pi())
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8.660254037844387e-01 5.000000000000001e-01 -1.000000000000000e+00