#  Math: Calculate arccosine in radians

This action is in beta and the function or availability may change unexpectedly.

Use this action to calculate the arccosine of a trigonometric ratio. Arccosine is the inverse of cosine. For example, if the `cos(.5) = 0.87758256 rad`, then the `arccos(0.54630249) = .5 rad`

To learn more, consider starting at the Inverse Trigonometric functions Wikipedia article.

In trigonometry, `arccos(x)` is sometimes notated as `cos-1(x)`, as it is the inverse of cosine.

###### note
• Note: This action outputs to radians. To convert radians to degrees, use the Radians to degrees action

## Use Case Use arccosine to calculate an angle’s measurement when the cosine of a ratio of the adjacent side and hypotenuse are known.

## How to configure this action When configuring this action, reference a Integer or decimal field in the Value field configuration. How do I reference a field?

For more advanced math, use Javascript with the Field: Field Formulas action.

## Fields for this action • #### Value • The integer or decimal to perform the operation on.
• #### Output field prefix • To help keep output fields organized, choose an output field prefix to add to the beginning of each output field name as this action may output more than one field.

## What will this output? This action may generate multiple fields. To help keep output fields organized, the prefix above will be added to the beginning of each of the output field names, separated by two dashes. Each field will result as:`{{output-field-prefix--output-field}}`.

### Output fields for this action • #### Result • The result of the operation. This action outputs in radians. The output is a decimal type field.
• For example, For example, `arccos(0.87758256 rad) = `0.5` radians.

## Get help with a problem or question If something’s not working as expected, or you’re looking for suggestions, check through the options below.

##### The results field is empty Math actions require integer or decimal values. If you enter an incompatible value for the input, the output may be blank. For example, attempting to perform an operation on the value `Marine Biologist` will always return an empty field.

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