Geometry Explorer Help
Exploring in a Hyperbolic World:
Using Geometry Explorer
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Windows, Tools, etc.:
Working in the Poincare model with Geometry Explorer is essentially
no different than working with the Euclidean model. Almost all of
the tools work in both environments, with a couple of notable exceptions
which are described below. Even recordings made in one environment
can be played back in the other environment. Thus, for example, the Koch
snowflake example can be recorded in a Euclidean canvas and played
back on a hyperbolic triangle, or vice-versa. This flexibility was deliberately
designed to give the user the maximum opportunity to explore and contrast
different geometric "universes" and thus to develop an intuition for how
it "feels' to live in one geometry versus another.
Differences Between Euclidean and Hyperbolic Canvases:
There are four main differences between the two environments:
-
In the Euclidean canvas the parallel button in the tool panel will
result in the unique parallel being created, once a linear object (segment,
ray, or line) and a point have been selected. In the Poincare (Hyperbolic)
model, using this tool (with the same selection of a linear object and
a point) will result in the creation of the two unique ultraparallels to
the given linear object and point. Thus, recordings made using parallels
in either environment will not be playable in the other environment.
-
In the Euclidean canvas, circles and arcs can be defined using three points.
This construction depends on the Euclidean parallel postulate, and thus
is not available in the Hyperbolic canvas.
-
There is no graph option available in the Poincare model.
-
Transformations cannot be defined in terms of measurements in the Poincare
model. (At least not yet!)