hugle
/ sumexpand.nb
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April 17, 2022 19:16
Expand summation expression and apply the distribution law
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| SumExpand[exp_] := | |
| exp /. Sum[c_, {i_, a_, b_}] :> | |
| Distribute[Sum[ExpandAll[c], {i, a, b}]]; | |
| rule = Sum[Times[Longest[u___], x___], {y_, z___}] :> | |
| Times[u] Sum[Times[x], {y, z}] /; (FreeQ[{u}, y]); | |
| SumSimplify[exp_] := SumExpand[exp] /. rule |