(PHP 4, PHP 5, PHP 7)
atan — 锟斤拷锟斤拷锟斤拷
$arg
) : float
锟斤拷锟斤拷 arg 锟侥凤拷锟斤拷锟斤拷值锟斤拷锟斤拷位锟角伙拷锟饺★拷atan() 锟斤拷
tan() 锟侥凤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷思锟斤拷锟斤拷
atan() 锟斤拷围锟斤拷锟矫匡拷锟街碉拷锟斤拷锟�
a==tan(atan(a))锟斤拷
arg要锟斤拷锟斤拷牟锟斤拷锟�
arg 锟侥凤拷锟斤拷锟叫伙拷锟饺★拷