arctangent

基本解釋

Calculates the arctangent of the given number.
計算給定數(shù)值的反正切函數(shù)值。
Expression to compute the arctangent of (float).
要計算反正切的表達(dá)式（浮點小數(shù)型）。
Computes the arctangent (in radians) of the specified argument.
計算指定參數(shù)的反正切（按弧度）。
The atan() function returns the arctangent of a number as a numeric value between -PI/2 and PI/2 radians.
函數(shù)的作用是：返回一個指定數(shù)值參數(shù)的反正切值。
The method sets up a mapping table which directly relates to the dynamic display range and has only 256 entries using an inverse mapping method instead of calculating the arctangent value directly.
該方法并不直接計算反正切值,而是采取反向映射的辦法,建立一個直接和顯示動態(tài)范圍有關(guān)、長度僅為256的映射表。