# Firemath - The Equation Editor

## Example: Gamma function

This is our single mouse-click example. It
demonstrates how Firemath's built in keyboard support can be utilized.
Further information on this topic is summarized on our page about
keyboard editing.

Start with pressing 'G' and notice how the text field gets on focus.
The 'G' in the text field can be inserted as a function via Shift-Alt-U
before key '(' inserts the desired fences. Since the cursor is already
located within the fences, we can immediately insert the beta-variable.
This can most easily be done by pressing 'b' followed by Ctrl-Alt-g.
Move the cursor to the very right by usage of the cursor keys. Pressing
'=' on your keyboard immediately inserts the equal operator and we arrive at

Type 'lim' and insert this exression as an operator via Shift-Alt-P. Press the <Left>-key and add under- overscripts via Shift-Alt-M. Typing 'n' followed by Shift-Alt-i inserts the variable as an identifier, while the '!' and '$' on your keyboard immediately insert the arrow and the infinity sign. So far, the intermediate result of our efforts looks like

$$G\left(\mathrm{\beta}\right)=\underset{n\to \infty}{lim}$$ Move the cursor to the very right before pressing Shift-Alt-L to get the fraction. In the nominator insert an 'n'-identifier as above. Now, by pressing Shift-Alt-T the text field is set on focus. This needs to be done to insert the '!', since otherwise we get an arrow as above. The '!' in the text field should be inserted as an operator via Shift-Alt-P. Once again insert an 'n'-identifier, move the cursor left one step and add sub- superscripts via Shift-Alt-N. For the superscript press 'b' followed by Ctrl-Alt-G followed by pressing the '-' key followed by pressing '1'. Insert the '1' via Shift-Alt-i. Move the cursor into the denominator and press the 'b' key followed by Ctrl-Alt-G in order to arrive at $$G\left(\mathrm{\beta}\right)=\underset{n\to \infty}{lim}\frac{n!{n}^{\mathrm{\beta}-1}}{\mathrm{\beta}}$$ The final steps should be clear now. Use the '(' key to insert the fences and the '+' and '-' keys for the corresponding operators. It's the central dots, which require the mouse click mentioned above. At the end you should arrive at $$G\left(\mathrm{\beta}\right)=\underset{n\to \infty}{lim}\frac{n!{n}^{\mathrm{\beta}-1}}{\mathrm{\beta}\left(\mathrm{\beta}+1\right)\xb7\xb7\xb7\left(\mathrm{\beta}+n-1\right)}$$