Many of the programs I’ve covered in the past have have been
desktop-environment-agnostic—all they required was some sort of
graphical display running. This article looks at one of the programs
available in the KDE desktop environment, KAlgebra.
You can use your distribution’s
package management system to install it, or you can use Discover,
KDE’s package manager. After it’s installed, you can start it
from the command line or the launch menu.
When you first start KAlgebra, you get a blank slate to start doing
Figure 1. When you start KAlgebra, you get a blank canvas for doing
The screen layout is a large main pane
where all of the calculations and their results are displayed. At the
top of this pane are four tabs: Calculator, 2D
Graph, 3D Graph and Dictionary.
There’s also a
smaller pane on the right-hand side used for different purposes
for each tab.
In the calculator tab, the side pane gives a list of
variables, including predefined variables for things like pi
or euler, available when you start your new session. You can add new
variables with the following syntax:
a := 3
This creates a new variable named
a with an initial value of
3. This new variable also will be visible in the list on the right-hand
side. Using these variables is as easy as executing them. For example,
you can double it with the following:
a * 2
There is a special variable called
ans that you can use to get the
result from your most recent calculation. All of the standard mathematical
operators are available for doing calculations.
Figure 2. KAlgebra lets you create your own variables and functions for
even more complex calculations.
There’s also a complete set of functions for doing more
complex calculations, such as trigonometric
functions, mathematical functions like absolute value or floor, and even
calculus functions like finding the derivative. For instance, the following
lets you find the sine of 45 degrees:
You also can define your own functions using the
->. If you want to create a function that
calculates cubes, you could do this:
x -> x^3
This is pretty hard to use, so you may want to assign it to a variable
cube := x -> x^3
You then can use it just like any other function, and it also shows up in
the list of variables on the right-hand side pane.
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