Maxima Function
intosum (expr)
Moves multiplicative factors outside a summation to inside.
If the index is used in the
outside expression, then the function tries to find a reasonable
index, the same as it does for sumcontract
. This is essentially the
reverse idea of the outative
property of summations, but note that it
does not remove this property, it only bypasses it.
In some cases,
a scanmap (multthru, expr)
may be necessary before the intosum
.