運算式 4: left parenthesis, "t" times cos left parenthesis, "a" , right parenthesis , "t" times sin left parenthesis, "a" , right parenthesis , right parenthesist·cosa,t·sina
4
運算式 5: tangent left parenthesis, "x" , right parenthesistanx
5
運算式 6: left parenthesis, "a" , tan left parenthesis, "a" , right parenthesis , right parenthesisa,tana
