# Scala - Math acos() Method

The Scala Math acos() method returns arc cosine of a value. The return value will be in the range 0 through 𝜋. In special cases it returns the following:

• If the argument is NaN or its absolute value is greater than 1, then the result is NaN.

Note: acos() is the inverse of cos().

### Syntax

```def acos(x: Double): Double = scala.lang.Math.acos(x)
```

### Parameters

 `x` Specify the value.

### Return Value

Returns the arc cosine of the value.

NA.

### Example:

In the example below, acos() method is used to find out the arc cosine of a given value.

```import scala.math._

object MainObject {
def main(args: Array[String]) {
println(s"acos(-1) = \${acos(-1)}");
println(s"acos(0.5) = \${acos(0.5)}");
println(s"acos(0) = \${acos(0)}");
println(s"acos(0.5) = \${acos(0.5)}");
println(s"acos(1) = \${acos(1)}");
println(s"acos(Double.NaN) = \${acos(Double.NaN)}");
println(s"acos(2) = \${acos(2)}");
println("acos(Double.PositiveInfinity) = "
+ acos(Double.PositiveInfinity));
}
}
```

The output of the above code will be:

```acos(-1) = 3.141592653589793
acos(0.5) = 1.0471975511965979
acos(0) = 1.5707963267948966
acos(0.5) = 1.0471975511965979
acos(1) = 0.0
acos(Double.NaN) = NaN
acos(2) = NaN
acos(Double.PositiveInfinity) = NaN
```

❮ Scala - Math Methods

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