math:cos/1
返回一个数字的余弦值
用法：
cos(X)
返回一个数字的余弦值
Cos = math:cos(90),
io:format("Cos is ~p~n", [Cos]).
Pi = math:pi(),
Cos = math:cos(2 * Pi),
io:format("Cos is ~p~n", [Cos]).
返回一个数字的余弦值
用法：
cos(X)
返回一个数字的余弦值
Cos = math:cos(90),
io:format("Cos is ~p~n", [Cos]).
Pi = math:pi(),
Cos = math:cos(2 * Pi),
io:format("Cos is ~p~n", [Cos]).