表达式4: left parenthesis, "f" left parenthesis, "A" , right parenthesis plus "t" left parenthesis, "f" left parenthesis, "B" , right parenthesis minus "f" left parenthesis, "A" , right parenthesis , right parenthesis , "g" left parenthesis, "A" , right parenthesis plus "t" left parenthesis, "g" left parenthesis, "B" , right parenthesis minus "g" left parenthesis, "A" , right parenthesis , right parenthesis , right parenthesisfA+tfB−fA,gA+tgB−gA
00
定义域t最小值：
less than or equal to "t" less than or equal to≤t≤
11
定义域t最大值：
4
表达式5: left parenthesis, "t" "f" left parenthesis, "A" , right parenthesis , "t" "g" left parenthesis, "A" , right parenthesis , right parenthesistfA,tgA
00
定义域t最小值：
less than or equal to "t" less than or equal to≤t≤
11
定义域t最大值：
5
表达式6: "f" left parenthesis, "x" , right parenthesis equals cosine StartFraction, 2 pi "x" Over "L" , EndFractionfx=cos2πxL
6
表达式7: "g" left parenthesis, "x" , right parenthesis equals sine StartFraction, 2 pi "x" Over "L" , EndFractiongx=sin2πxL
