# Difference between revisions of "CAS View" This view is part of GeoGebra user interface.

## Basic input

• Enter: evaluate input
• Ctrl + Enter: check input but do no evaluate input, e.g. b + b stays b + b. Note that assignments are always evaluated, e.g. a := 5
• In an empty row type
• Space bar for previous output
• `)` for previous output in parentheses
• `=` for previous input
• Suppress output with a semicolon at the end of your input, e.g. `a := 5;`

## Toolbar

• Clicking a button in the toolbar applies a command to the currently edited row
• You can select part of the input text to only apply the operation to this selected part

## Variables

### Assignments & Connection with GeoGebra

• Assignments use the := notation, e.g. `b := 5`, `a(n) := 2n + 3`
• To free up a variable name again, use `Delete[b]` or `b :=`
• Variables and functions are always shared between the CAS view and GeoGebra if possible. If you define `b:=5` in the CAS view, then you can use b in all of GeoGebra. If you have a function `f(x)=x^2` in GeoGebra, you can also use this function in the CAS view.
Note:
The output will always be just the term AFTER the :=, e.g. if you type b:=5 the output will be 5.

### Row References

You can refer to other rows in the CAS view in two ways

• Static row references insert text from another row, so your input is changed.
• `#` inserts the previous output
• `#5` inserts the output of row 5
• Dynamic row references use text from another row, but don't change your input.
• `\$` inserts the previous output
• `\$5` inserts the output of row 5

## Equations

• Equations are written using the simple Equals sign, e.g. `3x + 5 = 7`
• You can perform arithmetic operations on equations, e.g. `(3x + 5 = 7) - 5` subtracts 5 from both sides of the equation. This is useful for manual equation solving.
• `LeftSide[3x + 5 = 7]` returns 3 x + 5 and `RightSide[3x + 5 = 7]` returns 7

## Commands and Tools

For a complete list of commands and tools see CAS Commands and CAS tools.

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