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Permutation of vertices of pascal's hexagon

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pascal1.mws

Permutation of Vertices of Pascal's Hexagon

dr.Laczik Blint

Technical University of Budapest, Hungary

mail: laczik@goliat.eik.bme.hu

Pascal's theorem (1640) says:
If a hexagon
H[1] =(123456) is inscribed in a conic, then opposite sides intersect in three points

P[1] =(12.45), Q[1] = (23.56), R[1] =(34.61) which are collinear.

The representation of the hexagon H[1] and intersection points of opposite sides its by symbol is following:

H[1] := matrix([[12, 23, 34], [45, 56, 61], [P[1], ...

By the way of elementar combinatorics can be proof that the number of different hexagons H[i] is 60, and the number of different points P[i] , Q[i] , R[i] the intersections opposite sides of all hexagons are 45.

Let's show this special projective configuration by Maple.!

> restart; with(combstruct); with(combinat); with(geo...

Warning, new definition for Chi

Warning, new definition for draw

> U := permute([1, 2, 3, 4, 5]); h := numbperm(5); fo...

> circle(C,x^2+y^2 = 1,[x, y],centername = ``); for i...

Let's make coordinates 6 randpoints P.i of circle C and the lines l.i through of points recommanded sequence cc[z][i] and cc[z][i+1] . cc[z][i] and cc[z][i+1] are element of by permutations generated points.

For example one of hexagons (z = 11) and its sides

> z := 11; cc[z]; for i to 6 do line(l.i,[P.cc[z][i],...

[6, 1, 3, 5, 2, 4, 6]

l1, `line through of points`, 6, ` and `, 1

l2, `line through of points`, 1, ` and `, 3

l3, `line through of points`, 3, ` and `, 5

l4, `line through of points`, 5, ` and `, 2

l5, `line through of points`, 2, ` and `, 4

l6, `line through of points`, 4, ` and `, 6

The intersections of opposite sides l.1, l.4 is P, l.2, l.5 is Q, l.3, l.6 is S.

Make the line T_1 through of the points P and S, T_2 through of the points Q and S, T_3 through of the points P and Q,

and show the Pascal's hexagon and line.

> intersection(P,l.1,l.4); intersection(Q,l.2,l.5); i...
intersection(P,l.1,l.4); intersection(Q,l.2,l.5); i...
intersection(P,l.1,l.4); intersection(Q,l.2,l.5); i...
intersection(P,l.1,l.4); intersection(Q,l.2,l.5); i...
intersection(P,l.1,l.4); intersection(Q,l.2,l.5); i...
intersection(P,l.1,l.4); intersection(Q,l.2,l.5); i...

The line T_1 through of points P and S, the line T_2 through of points Q and S, or the line T_3 through Q and P are equal by accuracy of calculating method - look the original Pascal's theorem.

> Y.1 := solve(Equation(T_1),y); Y.2 := solve(Equatio...

Y1 := -.3605438025-1.513607195*x

Y2 := -.3605437997-1.513607193*x

Y3 := -.3605438019-1.513607196*x

> Y.1-(Y.2); Y.1-(Y.3); Y.2-(Y.3)

-.28e-8-.2e-8*x

-.6e-9+.1e-8*x

.22e-8+.3e-8*x

> pic := draw({C(color = black), P.1, P.2, P.3, P.4, ...
pic := draw({C(color = black), P.1, P.2, P.3, P.4, ...
pic := draw({C(color = black), P.1, P.2, P.3, P.4, ...

[Maple Plot]

Finally make the all hexagons, points and lines of combinatorical structure cc[i]. By simple way of representation show the full combinatorical and geometrical structure.

> for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...
for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...
for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...
for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...
for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...
for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...
for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...
for q to h do for i to 6 do line(l.i,[P.cc[q][i], P...

> display({seq(kep[w],w = 1 .. h)},pic,title = `Pasca...

[Maple Plot]

> display({seq(kep[w],w = 1 .. h)},pic,title = `Part ...

[Maple Plot]

> display({seq(kep[w],w = 1 .. h)},pic,title = `Part ...

[Maple Plot]

>