# Cos Function

Calculates the cosine of an angle. The angle is specified in radians. The result lies between -1 and 1.

Using the angle Alpha, the Cos-Function calculates the ratio of the length of the side that is adjacent to the angle, divided by the length of the hypotenuse in a right-angled triangle.

Cos(Alpha) = Adjacent/Hypotenuse

## Syntax:

```
Cos (Number)
```

## Return value:

Double

## Parameters:

Number: Numeric expression that specifies an angle in radians that you want to calculate the cosine for.

To convert degrees to radians, multiply degrees by pi/180. To convert radians to degrees, multiply radians by 180/pi.

degree=(radian*180)/pi

radian=(degree*pi)/180

Pi is here the fixed circle constant with the rounded value 3.14159...

## Example:

```
' The following example allows for a right-angled triangle the input of
' secant and angle (in degrees) and calculates the length of the hypotenuse:
Sub ExampleCosinus
' rounded Pi = 3.14159
Dim d1 As Double, dAngle As Double
d1 = InputBox("Enter the length of the adjacent side: ","Adjacent")
dAngle = InputBox("Enter the angle Alpha (in degrees): ","Alpha")
Print "The length of the hypothenuse is"; (d1 / cos (dAngle * Pi / 180))
End Sub
```