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This is a demonstration of how to do the
GeoGebra ship challenge. First we need to have
the ship image somewhere where we can find it.
So for example, I have it here on my desktop.
Secondly, we are going to input a formula so we
need to have the input bar open.
So we go to View and down here to Input and
over here to Show.
Next it is probably a good idea to have the
Algebra view while we are working. So we go to
View again and then Algebra.
And finally, we really do not want to see the
axes so we will go over here to an empty space
in the drawing pad, right-click and deselect Axes.
Now we are ready to construct. The first thing is
the line segment. So we go to the line tools. This
is the line tool. We want a segment.
So we click on the little arrow. Get “Segment
between two points”. Click to activate it.
Click down here towards the bottom and up here
towards the top. Now we want to move the
labels A and B underneath the line.
We take our Move tool (activate it) and pull (click
and drag) the labels underneath the points.
The next thing we need is the slider to control the
point moving from A to B. So we activate the
slider tool. Click up here in the left corner.
We want to name it t so we immediately just type
t. That will rename it. We want it to go from 0 so
we take off -5.
We want it to go to 1 (maximum of 1). And then in
order for the animation to be smooth, we want
the increment to be 0.01.
So 0.01 or one one-hundredths. So that it makes
a hundred steps between 0 and 1. The rest of
the things we will just leave and apply.
It is good to move the slider to the middle. So we
will take the move tool (activate it) and move the
slider towards the middle.
Now we need the point P that moves with t. If
you watched the mathcast, we saw that the
formula is P equals (1-t) times A plus t times B.
We click down in the input bar and start typing
P=(1-t)*A+t*B and we hit enter.
Now we see that P is on the line (as it should be).
We want to check that it will move as t goes. So
we come up to the slider on a blank place,
right-click and choose Animation on. And we see
that the point goes up and down. Let us stop the
animation and attach our ship to point P.
So we want to insert the image, but have it
attached to the point P. The image tool is
underneath the slider tools.
So we click on the little arrow, activate “Insert
image”. Now this is critical. We need to make P
glow. So we put our mouse pointer on P.
Now it is glowing. Click and go to our desktop.
Here is our little picture ship. Open. And there it is.
Notice that because it is a png, it is transparent.
So we can actually see through it. But we are
going to hide the segment and the point P now.
How do we do that? We use a checkbox to hide
and show objects. So activate the checkbox tool.
Click underneath the slider and we start typing
“Show segment and point”. Now come down
here to the down arrow, click on it.
Get the segment. Again click on the down arrow
and get point P. Apply.
Currently it is selected and we can see the
segment and the point. Take the move tool. Let us
move this up a little bit here.
Now let us deselect it and start the animation and
everything looks great.
Now, before you go to your moodle, decide
whether you want the algebra view to be visible.
If you don’t, then go to View and deselect
Algebra. Then resize your window to be the size
you want.
We do not want to go all of the way over to B
because the ship will come to the right of B.
Now do Ctrl+Shift+M and our code is in the
clipboard. We can paste it into our wiki or our
moodle.
Okay – that’s it.