How to attach pen tool to endpoint of a segment in Geogebra?

Question

How to attach pen tool to endpoint of a segment (or curve) in Geogebra such that by moving segment, the pen draw a curve? for example I want to draw animated Cycloid in Geogebra but I don't know how to do it?

Answer 1

You can make a point leave a trace as it moves by checking the box show trace:

Sorry, I don't have it in English. I used the online geogebra tool.

EDIT:

There is also a command called Locus. And this is actually a better way since tracing doesn't give you a continous curve.

From the manual:

Locus[Point Q, Point P] Returns the locus curve of the point Q, which depends on the point P.
Note: Point P needs to be a point on an object (e. g. line, segment, circle).

So, if your movable point is $A$ and the point to trace is $B$, type Locus[A,B] into the console and you get the curve for the point $B$ as $A$ moves along its curve.

Answer 2

Instead of pen tool, you can also build the curve yourself using the Curve command.

For example, following commands create a cycloid with the circle. How much the cycloid is join is controlled by the Slider T. After you customize individual elements through the GUI, turning animate on T will give you an animated cycloid.

X(t) := t - Sin[t]
Y(t) := 1 - Cos[t]
T : Slider[0,4*Pi,0.1,1]
A : (T,1) 
B : (X(T),Y(T)) 
s : Segment[A,B] 
c1 : Circle[A,1] 
ca : Curve[X(t),Y(t),t,0,T] 
cb : Curve[X(t),Y(t),t,T,4*Pi]