New in Wolfram Mathematica 7: Enhanced Typesetting Automation  previous | next 
Typeset Derivatives and Differential Equations Just as in Textbooks
In[1]:=

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TraditionalForm[

 Sum[With[{i = i, j = j}, 

   HoldForm[D[\[Phi][x, y], {x, i}, {y, j}]]], {i, 5}, {j, 5}]]
Out[1]=