MATLAB: Symbolic vectors ‘invalid variable name’

MATLABsymbolicSymbolic Math Toolboxsyms

I am attempting to create a symbolic vector precisely like the one explained here.
Starting with a fresh MATLAB environment, the code:
syms a [1 4]
Causes an error: "Error using syms (line 222). Invalid variable name."
This code creates a 1×1 sym object 'a', but not the expected 1×4 symbolic vector. The exact same error occurs on my own computer running R2018a (academic) and university computers running R2018b (academic). The syms toolbox seems to be working fine as simply using 'syms a' works fine.
All other similar errors seem to be caused by a missing symbolic toolbox or with more complicated code. I can't figure out why something so simple is failing on both systems. Any suggestions are very welcome.

Best Answer

sym('a',[1 4])
doc sym
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