\(\left\{ {\begin{array}{*{20}{c}}{{u_1} = 2}\\{{u_{n + 1}} = {u_n} + a\left[ {{{\left( {1 + a} \right)}^n} + {{\left( {1 - a} \right)}^n}} \right]}\end{array}} \right.\)
A.\(\left\{ {\begin{array}{*{20}{c}}{{u_1} = 2}\\{{u_{n + 1}} = {u_n} + a\left[ {{{\left( {1 + a} \right)}^n} + {{\left( {1 - a} \right)}^n}} \right]}\end{array}} \right.\)
B.\(\left\{ {\begin{array}{*{20}{c}}{{u_1} = 2}\\{{u_{n + 1}} = {u_n} + 2a\left[ {{{\left( {1 + a} \right)}^n} - {{\left( {1 - a} \right)}^n}} \right]}\end{array}} \right.\)
C.\(\left\{ {\begin{array}{*{20}{c}}{{u_1} = 2}\\{{u_{n + 1}} = 2{u_n} + a\left[ {{{\left( {1 + a} \right)}^n} - {{\left( {1 - a} \right)}^n}} \right]}\end{array}} \right.\)
D.\(\left\{ {\begin{array}{*{20}{c}}{{u_1} = 2}\\{{u_{n + 1}} = {u_n} + a\left[ {{{\left( {1 + a} \right)}^n} - {{\left( {1 - a} \right)}^n}} \right]}\end{array}} \right.\)