Lời giải chi tiết:
\( \sqrt {\dfrac{{2 - \sqrt 3 }}{{2 + \sqrt 3 }}} + \sqrt {\dfrac{{2 + \sqrt 3 }}{{2 - \sqrt 3 }}} \\ = \sqrt {\left( {2 - \sqrt 3 } \right)\left( {2 - \sqrt 3 } \right)} + \sqrt {\left( {2 + \sqrt 3 } \right)\left( {2 + \sqrt 3 } \right)} \\ = \sqrt {{{\left( {2 - \sqrt 3 } \right)}^2}} + \sqrt {{{\left( {2 + \sqrt 3 } \right)}^2}} \\ = 2 - \sqrt 3 + 2 + \sqrt 3 = 4 \)
\(\boxed{NTT}\)