恐龙进化成鸟类的过程:arctan0.75=_

arctan0.75=_ arctan0.75=_ arctan0.0433=? 帮我查查 arctan0等于多少？ arctan1 arctan0是等于多少? Show me your ticket. =Let _ _ _ _ _ your ticket. help~~~~ =_= !@#$%^&*()_+$% !~_*_*#!_&_! -_- ???!!!