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The equation writer

To run it, choose in the menu bar Edit->Windows->Equation or click on the yellow eqw button. Press the yellow hist key to go back to the history. You can also select an expression in the history and click on the blue ->eqw button.
\includegraphics[width=\textwidth]{xcas2en}

In this mode, expressions are stored as graph with operator as nodes, and arguments as end vertices. To modify an argument, click on it, modify and type the up arrow or click somewhere else. You can modify an expression by selecting it, this will copy it to the commandline, modify the commandline and type Enter to replace the selection by the commandline. Note that in selection mode, the direction keys change the selection according to the move in the graph of the expression. It is also possible to :

If you want to copy a subexpression elsewhere, select it, then click on copy in the mode buttons bar, select where you want to copy, and click on paste.

To leave this mode, you can click on ->cmd (copies the whole expression in commandline) or shift ->cmd (copies only the selection). Of course you can also click on a yellow button of the bandeau.

Example : enter eqw, type x then up arrow, then ^, then 100, up arrow, up arrow again to select the whole expression (x100), then - then 1, then up arrow twice to select x100 - 1 (remark : you can also enter directly x^100-1 and up arrow, the method above was shown because for more complex expressions it is less error prone). Select factor in the Cas menu, then down arrow, right arrow, etc. to move the selection. Select x2 + 1 with the arrow keys or with the mouse, click on ^ then 2 then up arrow twice.

Remark : you can edit the history entries in the same manner. Note that when you press Enter, all changes are activated and xcas will recompute all answers (starting from the first modification). If you press Esc, all changes are cancelled.


next up previous contents
Next: Geometry and graphics Up: Xcas tutorial Previous: First steps   Contents
giac documentation written by Bernard Parisse