Dynamical Geometry Sketches: Introduction
Martti E. Pesonen
Let E be the two dimensional Euclidean plane.
Let us assume points, lines and segments to be familiar, also the notion of
distance assumed to be known.
Example Sketch
Getting familiar with Sketches: experimenting with circles
Recall a definition of cirle:
Let P be a point and AB a segment in the plane.
A cirle with radius AB and center at P is
the set of all points that are at distance of the length of the segment AB from
the point P. We call the center also focus.
Instructions for experimentation
You may want to get used to this kind of dynamical sketches.
Feel free to move all active (usually red) points, just to see what happens!
If you are not yet familiar with
1) Move and Animate facilities,
2) resetting the sketch and clearing traces,
be sure to try them all now. Try to remember:
You may use any combination of Move and Animate buttons, and combine manual dragging.
You can reset the sketch by pushing 'R' on the keyboard.
You can clear the drawn traces by mouse-clicking the red cross at the lower right corner.
Can you produce figures like these?
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Other sketches contain various kinds of mathematical tasks.
Some of them require more explicit or formal mathematical reasoning, and an
unprejudiced attitude for experimentation!
Link to our collection of www workheets based of dynamical sketches
Animation Catalogue