error regarding syms symbolic mathtool

i have an error regarding syms,i keyed in all in syms in symbolic however there are stilll some error,

thanks in advance

Answer 1

[Steven Lord]

You're missing an operator between Rid and (R1+Rf). If you want to multiply those two quantities you need to explicitly specify the multiplication operator *.

Answer 2

[Star Strider]

Yes, there is.

The expression is missing a multiplication operator —

Rid*(R1+Rf)

↑ ← HERE

MATLAB does not recognise implicit multiplication.