ACOS
Returns the inverse cosine value of a numeric expression
Syntax
ACOS( expr )
Arguments
Parameter |
Description |
---|---|
|
Numeric expression in range |
Returns
Always returns a floating point result of the inverse cosine, in radians.
Notes
Valid inputs for an inverse cosine are in the range
[ -1.0 , 1.0]
. Inputs exceeding this range will result in an error.The result is given in radians, in the range
[0, π]
.If the input value is NULL, the result is NULL.
Examples
For these examples, consider the following table and contents:
CREATE TABLE trig(i INT, f DOUBLE);
INSERT INTO trig VALUES (0,0.0), (1,-0.866)
, (2,-0.707), (3,-0.5)
, (4,0.5), (5,0.707)
, (6, 0.866), (7, 1);
Inverse cosine of 0 (= π/2)
numbers=> SELECT ACOS(0);
acos
-------------------
1.5707963267948966
Computing inverse cosine for a column
numbers=> SELECT f, ACOS(f) FROM trig;
f | acos
------+-----
0 | 1.57
-0.87 | 2.62
-0.71 | 2.36
-0.5 | 2.09
0.5 | 1.05
0.71 | 0.79
0.87 | 0.52
1 | 0