1.14 Kig

Kig [11] a free ( GPL) analog of GSP for KDE, bit more to calculus-oriented, part of KDE Edutainment Project .

Plus:

• can read simple files from KGeo , KSeg , Dr. Geo and Cabri Geometry (but not very good at this so far).

Minus:

• It takes more time to create the same construction than in GSP,
• there is no function to create a java applet for pubilshig on web, no measurements, no calculations.

1.15 Kgeo

Kgeo [12] a free ( GPL) analog of GSP for KDE, bit more to calculus-oriented. ???

1.16 KSEG

KSEG [13] free ( GLP ) analog of GSP which has few important unique fithers.

Plus:

• very comfortable interface,
• very fast,
• support large constructions,
• makes better loci.
• easy to use editable macro with support for recursion,
• multilingual,

Minus:

• there is no direct way to put a point on locus,
• there is no function to create a java applet for publishing on web.

If you plan to do some heavy, complicated constructions in Euclidean geometry this is for you.

2 Principle of Continuity

Rigt now all IGS exapt Cinderella suffer from Continuity problem. Here is the test to check whether a particular program has Continuity problem:

Construct the orthocenter of triangle and three mid points (say A', B' C' ) between vertexes and orthocenter.

Construct a circumcircle of A'B'C' .

This is the nine-point circle, it intersect each side of the original triangle at two points: the base of altitude and midpoint. construct an intersection of one side with the circle at mid point now move opposite vertex of the original triangle, if the constructed point does not move when base of altitude movies trough it that probably means that your program does not have Continuity problem.

Software

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