Warning, if e is meant to be the exponential e, use command/symbol completion or palettes to enter this special symbol, or use the exp function - Maple Programming Help

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Warning, if e is meant to be the exponential e, use command/symbol completion or palettes to enter this special symbol, or use the exp function

Description

In Maple, you can use almost any letter as as a variable, even when that letter is also used to represent a particular mathematical symbol or constant, such as the exponential constant $ⅇ,$ the differential symbol $ⅆ$, or the imaginary unit $i$.  To achieve this flexibility, these characters need to be entered as special symbols.

This warning occurs if you type something that resembles an expression with the exponential $ⅇ$, but use a variable $e$, not the exponential symbol $ⅇ$. In order to enter the exponential function, use command/symbol completion, the palettes, or the exp function, as demonstrated in the examples below.

Note the difference in typesetting: the variable $e$ is displayed in italics, whereas the exponential constant is displayed without italics: $ⅇ.$ Using the wrong one leads to unexpected results, and often, this warning.

Variable $\mathbit{e}$:

 > $\mathrm{diff}\left({e}^{x},x\right)$
 ${{e}}^{{x}}{}{\mathrm{ln}}{}\left({e}\right)$ (1.1)

Symbol $\mathbf{ⅇ}\mathbf{:}$

 > $\mathrm{diff}\left({ⅇ}^{x},x\right)$
 ${{ⅇ}}^{{x}}$ (1.2)

Examples

Example 1

Typing e by hand does not create an expression meaning the base of the natural logarithm ( ).  Instead, the e is simply a variable.

 > ${e}^{x}$
 ${{e}}^{{x}}$ (2.1)

Solution 1 - Use the command/symbol completion

Use command/symbol completion to enter the exponential constant $ⅇ$.  Start by typing e, then press Esc.  Select Exponential 'e' from the pop-up list.

 ${ⅇ}$ (2.2)

 > ${ⅇ}^{x}$
 ${{ⅇ}}^{{x}}$ (2.3)
 > $\mathrm{plot}\left({ⅇ}^{x},x\right)$

Solution 2 - Use the Palettes

The Expression palette provide templates for entering mathematical expressions.  It's useful when you want to write a power of $ⅇ$.  Alternatively, the Common Symbols palette has an entry for $ⅇ$ which you can incorporate into a larger expression.

To use the Expression palette, place your cursor in your document, then click the   template.  The placeholder is highlighted.  Type x.  Press enter to execute.

 > ${ⅇ}^{x}$
 ${{ⅇ}}^{{x}}$ (2.4)

Solution 3 - The exp Function

You can also use the exp function:

 > $\mathrm{exp}\left(x\right)$
 ${{ⅇ}}^{{x}}$ (2.5)

See the exp help page for additional information.