The attached image shows different results in symbolic optimization in using Vetorize Operator, and
consequently generates an error when using "FindRoot" function in the attached worksheet.

When Equations 1B & 2B are disabled and 1A & 2A enabled, "FindRoot" gives the result.

Vectorize error - Symbolic Optimization.sm (189.05 KiB) downloaded 1031 time(s).

if you initialize the vector Q, then it works

Q:mat(el(Q,1),el(Q,2),el(Q,3),el(Q,4),4,1)

sergio

Thank you! It works.

Your red vectorise is just a display, i.e: not an assignment.
Unlike the "red vectorise", the "blue vectorise" ASSIGNS the
vector required by FindRoots, thus immaterial wrt Symbolic/Numeric/NONE

The suggestion to initialise is not technical to me [just a comment].
It simply confuses matters. There is a long route to explore/clarify
the Smath Vectorise operator