# Atn Function

អនុគមន៍​ត្រីកោណ​មាត្រ​ដែល​ត្រឡប់​អ័ក្ស​តង់សង់​នៃ​កន្សោម​លេខ ។ តម្លៃ​ត្រឡប់​ស្ថិត​នៅ​ចន្លោះ​ពី -Pi/2 ទៅ +Pi/2 ។

The arctangent is the inverse of the tangent function. The Atn Function returns the angle "Alpha", expressed in radians, using the tangent of this angle. The function can also return the angle "Alpha" by comparing the ratio of the length of the side that is opposite of the angle to the length of the side that is adjacent to the angle in a right-angled triangle.

Atn(side opposite the angle/side adjacent to angle)= Alpha

### Syntax:

``````
Atn (Number As Double) As Double
``````

Double

### Parameters:

Number: Any numerical expression that represents the ratio of two sides of a right triangle. The Atn function returns the corresponding angle in radians (arctangent).

ដើម្បី​បម្លែង​រ៉ាដ្យង់​ជា​ដឺក្រេ គុណ​រ៉ាដ្យង់​នឹង 180/pi ។

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

### Error codes:

5 ការ​ហៅ​បែបបទ​មិន​ត្រឹមត្រូវ

### Example:

``````
REM The following example calculates for a right-angled triangle
REM the angle Alpha from the tangent of the angle Alpha:
Sub ExampleAtn
REM rounded Pi = 3.14159 is a predefined constant
Dim d1 As Double
Dim d2 As Double
d1 = InputBox("Enter the length of the side adjacent to the angle: ","Adjacent")
d2 = InputBox("Enter the length of the side opposite the angle: ","Opposite")
Print "The Alpha angle is"; (atn (d2/d1) * 180 / Pi); " degrees"
End Sub
``````