Код:
In[1]:= k = {{12, 13, 7}, {6, -1, 1}, {3, -2, 1}};
In[2]:= {2 k[[1]], k[[2]], k[[3]]}
Out[2]= {{24, 26, 14}, {6, -1, 1}, {3, -2, 1}}
In[3]:= Module[{kt=Transpose[k]}, Transpose[{2 kt[[1]], kt[[2]], kt[[3]]}]]
Out[3]= {{24, 13, 7}, {12, -1, 1}, {6, -2, 1}}
или
Код:
In[5]:= Array[If[#2==1, 2, 1] k[[#1]][[#2]] &, {Length[k],Length[k]}]
Out[5]= {{24, 13, 7}, {12, -1, 1}, {6, -2, 1}}
In[6]:= Array[If[#1==1, 2, 1] k[[#1]][[#2]] &, {Length[k],Length[k]}]
Out[6]= {{24, 26, 14}, {6, -1, 1}, {3, -2, 1}}