表达式1: left parenthesis, sin left parenthesis, "t" , right parenthesis , cos left parenthesis, "t" , right parenthesis , sin left parenthesis, 2 "t" , right parenthesis , right parenthesissint,cost,sin2t
定义域t最小值： 00
less than or equal to "t" less than or equal to≤t≤
