Return the arc cosine of different numbers:
The acos() function returns the arc cosine of a number.
Tip: acos(-1) returns the value of Pi.
Parameter | Description |
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number | Required. Specifies a number in range -1 to 1 |
Return Value: | The arc cosine of a number. Returns NAN if number is not in the range -1 to 1 |
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Return Type: | Float |
PHP Version: | 4+ |