<p class="Paragraph">Trigonometric function that returns the arctangent of a numeric expression. The return value is in the range -Pi/2 to +Pi/2.</p>
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<p class="Paragraph">The arctangent is the inverse of the tangent function. This means that the Atn Function returns the angle Alpha in radians using the tangent of this angle or the ratio of the length of the side opposite the angle to the length of the side adjacent to the angle in a right-angled triangle.</p>
<p class="Paragraph">Atn(side opposite the angle/side adjacent to angle)= Alpha</p>
<p class="Paragraph">Number: Any numeric expression that represents the ratio of two sides of a right triangle. The Atn function returns the arctangent, i.e., the corresponding angle in radians.</p>
<p class="Paragraph">To convert radians to degrees, multiply radians by 180/pi.</p>
<p class="Paragraph">degree=(radian*180)/pi</p>
<p class="Paragraph">radian=(degree*pi)/180</p>
<p class="Paragraph">Pi is here the fixed circle constant with the value 3.141592657... .</p>
<p class="P2">Example:</p>
<p class="PropText">REM The following example calculates for a right-angled triangle</p>
<p class="PropText">REM the angle Alpha from the tangent of the angle Alpha:</p>
<p class="PropText">Sub ExampleATN</p>
<p class="PropText">REM Pi = 3.1415926 is a predefined constant</p>
<p class="PropText">Dim d1 As Double</p>
<p class="PropText">Dim d2 As Double</p>
<p class="PropText">d1 = InputBox$ ("Enter the length of the side adjacent to the angle: ","Adjacent")</p>
<p class="PropText">d2 = InputBox$ (""Enter the length of the side opposite the angle: ","Opposite")</p>