# Weird subscript name in output [duplicate]

One of my first times using mathematica, I'm getting a weird Subscript(1,0) output when I try to solve a derivative. What is going on and how can I fix this?

• Try to avoid Subscript until you are more comfortable with Mathematica. For instance, try D[Subscript[c, t], c]. Just use cf,nf as variable names instead. – Marius Ladegård Meyer Mar 21 '15 at 17:54

The reason is, that the nicely formatted subscripts in the frontend looking like $c_f$ are no "real" variables, but are represented as Subscript[c,f]. You can see that, if you use FullForm on one of those subscript-lookalikes.
Therefore, your code does end up trying to create the derivative of the Mathematica-function Subscript, but of course there is no such thing. This is why you are left with that result.
Exchange any subscript with a more straightforward representation, e.g. (as suggested by Marius): cf instead of Subscript[c,f] etc.