Exploring the Input Bar

In this tutorial we show how to use the Input Bar and GeoGebra Commands.
The complete GeoGebra file is here: Tutorial-4.ggb.

Open a new GeoGebra worksheet.   I have selected Options > Labeling > No New Objects.

Place 5 points randomly.  We'll find the polynomial of degree 4 that best fits these points.

At the bottom right corner of your screen is the Command List.  Open it up to see what commands are available to you.  Select FitPoly.  Type the F1 key to see what form its argument takes.  You should see
  FitPoly[<list of points>, <degree of polynomial>]

Lists are sets of objects delimited by braces { }.  Type
  FitPoly[ { A, B, C, D, E }, 4 ]

Now move the points and see what happens.  Type  Integral[f(x), 2, 6]  to see its effects.

Click the (?) icon to the left of the Input Bar for more information. 

GeoGebra has some nice random number generation features.

P = (RandomBetween[1, 7], RandomBetween[1, 4] )

This generates a point with x-coordinate between 1 and 7 (inclusive) and y-coordinate between 1 and 4 (inclusive).

Typing Ctrl-R (View > Recompute All Objects) will regenerate the random numbers.

Create a slider named  a  and allow it to take values from -5 to 5.

Define  f(x) = x^3 + a x

Move the slider so a = -2.

    R = Root[ f(x) ]    and
    E = Extremum[ f(x) ]

See how GeoGebra creates multiple points and names.

See how these values change as the slider is moved.

One of the most powerful commands is Sequence.

Make a slider called  r  with values from 0 to 5.
Make a slider called  n  with values from 1 to 100, incrementing by 1.

Enter the command
Sequence[ (r cos( i 2π/n), r sin(i 2π/n)), i, 0, n-1 ]

To enter the π symbol, type Alt-p.  Be careful with parentheses.

This creates a sequence of points (the first argument in the command) as  i  goes from 0 to n-1.

Just for fun, right-click slider  r  and check Animation On.  Notice how a little Play/Pause button appears in the lower left corner of the Graphics View.

Final thoughts
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