Expression 5: "f" left parenthesis, "x" , right parenthesis equals StartFraction, "a" Over left parenthesis, 1 minus "t" , right parenthesis "e" Superscript, negative tan squared left parenthesis, StartNestedFraction, "x" NestedOver "b" , EndNestedFraction , right parenthesis , Baseline plus "t" "e" Superscript, tan squared left parenthesis, StartNestedFraction, "x" NestedOver "b" , EndNestedFraction , right parenthesis , Baseline , EndFractionfx=a1−te−tan2xb+tetan2xb