# ACOS

Returns the arccosine, or inverse cosine, of a number

## Syntax

```
ACOS(number)
```

## Arguments

| Argument | Description | Required |
| --- | --- | --- |
| `number` | The cosine of the angle you want and must be from -1 to 1 | Required |

## Examples

### Arccosine of 0 (90 degrees in radians)

=ACOS(0)

Result ⇒ 1.5708

### Arccosine of -1 (180 degrees in radians)

=ACOS(-1)

Result ⇒ 3.1416

### Arccosine of cell value

=ACOS(A1)

Result ⇒ 2.0944

|     |     |
| --- | --- |
|  | A |
| 1 | -0.5 |

## Related Functions

Other Math functions:

- [ABS](/content/docs/formulas/abs.html) \- Returns the absolute value of a number
- [ASIN](/content/docs/formulas/asin.html) \- Returns the arcsine, or inverse sine, of a number
- [ATAN](/content/docs/formulas/atan.html) \- Returns the arctangent, or inverse tangent, of a number
- [CEILING](/content/docs/formulas/ceiling.html) \- Rounds a number up to the nearest integer or to the nearest multiple of significance
- [COS](/content/docs/formulas/cos.html) \- Returns the cosine of the given angle
- [EXP](/content/docs/formulas/exp.html) \- Returns e raised to the power of a given number
- [FACT](/content/docs/formulas/fact.html) \- Returns the factorial of a number
- [FLOOR](/content/docs/formulas/floor.html) \- Rounds a number down to the nearest multiple of significance
- [INT](/content/docs/formulas/int.html) \- Rounds a number down to the nearest integer
- [LN](/content/docs/formulas/ln.html) \- Returns the natural logarithm of a number
- [LOG](/content/docs/formulas/log.html) \- Returns the logarithm of a number to a specified base
- [LOG10](/content/docs/formulas/log10.html) \- Returns the base-10 logarithm of a number
- [MOD](/content/docs/formulas/mod.html) \- Returns the remainder after a number is divided by a divisor
- [PI](/content/docs/formulas/pi.html) \- Returns the value of pi (π)
- [POWER](/content/docs/formulas/power.html) \- Returns the result of a number raised to a power
- [RAND](/content/docs/formulas/rand.html) \- Returns a random number greater than or equal to 0 and less than 1.
- [ROUND](/content/docs/formulas/round.html) \- Returns the number after rounding it to a certain number of decimal places.
- [ROUNDDOWN](/content/docs/formulas/rounddown.html) \- Returns a number rounded to a certain number of decimal places. ROUNDDOWN rounds all numbers down.
- [ROUNDUP](/content/docs/formulas/roundup.html) \- Returns a number rounded up to a certain number of decimal places. ROUNDUP rounds all numbers up.
- [SIGN](/content/docs/formulas/sign.html) \- Determines the sign of a number
- [SIN](/content/docs/formulas/sin.html) \- Returns the sine of the given angle
- [SQRT](/content/docs/formulas/sqrt.html) \- Returns the square root of a number
- [SUM](/content/docs/formulas/sum.html) \- Returns the sum of all numbers in the provided arguments
- [TAN](/content/docs/formulas/tan.html) \- Returns the tangent of the given angle
- [TRUNC](/content/docs/formulas/trunc.html) \- Truncates a number to an integer by removing the fractional part