# #StackBounty: #pgfplots #pgfmath pgfplots: x vs x

### Bounty: 50

• This question is a follow-up to this question ("pgfplots: Strange Bump in `tanh` Function").
• Stefan Pinnow, who knows a thing or two about `pgfplots`, provided an answer that distinguished between `addplot{tanh(x)};` and `addplot{tanh(x)};`(`x` vs `x` as the argument).
• In a comment, Stefan stated "My thought also was that tanh(x) is the same as tanh(x) but it seems that Lua "doesn’t like" "commands", i.e. `<something>`. But to my experience I never used x in addplot calls. Since this is easier to read and easier to type […]".
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• The current `pgfplots` manual (Revision 1.18.1 (2021/05/15)) states in Chapter 4.3.3 (Computing Coordinates with Mathematical Expressions): "In short: it is the same whether you write x or just x inside of math expressions.".
• Question: In what circumstances does it matter whether I use `x` or `x` in an `addplot` argument?