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Anticomplement


The anticomplement of a point P in a reference triangle DeltaABC is a point P^' satisfying the vector equation

P^'G^->=2GP^->,
(1)

where G is the triangle centroid of DeltaABC (Kimberling 1998, p. 150).

The anticomplement of a point with center function alpha:beta:gamma is therefore given by the point with trilinears

The anticomplement of a line

lalpha+mbeta+ngamma=0
(3)

is given by the line

a^2(cm+bn)alpha+b^2(cl+an)beta+c^2(bl+am)gamma=0.
(4)

The following table summarizes the anticomplements of a number of named lines, including their Kimberling line and center designations.

L_n line L_n anticomplement line
L_1 antiorthic axis L_(213)
L_(523) Brocard axis *
L_(32) de Longchamps line L_(39)
L_(647) Euler line L_(647) Euler line
L_(526) Fermat axis *
L_(55) Gergonne line L_(31)
L_2 Lemoine axis *
L_(649) Nagel line L_(649) Nagel line
L_(657) Soddy line *

The following table summarizes the anticomplements of a number of named circles.

The following table lists some points and their anticomplements using Kimberling center designations.

P P^'
X_1 X_8
X_2 X_2
X_3 X_4
X_4 X_(20)
X_5 X_3
X_6 X_(69)
X_7 X_(144)
X_8 X_(145)
X_9 X_7
X_(10) X_1
X_(11) X_(100)
X_(12)
X_(13) X_(616)
X_(14) X_(617)
X_(15) X_(621)
X_(16) X_(622)
X_(17) X_(627)
X_(18) X_(628)
X_(19)
X_(20)
X_(21) X_(2475)
X_(25) X_(1370)
X_(32) X_(315)
X_(37) X_(75)
X_(39) X_(76)
X_(40) X_(962)
X_(44) X_(320)
X_(57) X_(329)
X_(58) X_(1330)
X_(61) X_(633)
X_(62) X_(634)
X_(69) X_(193)
X_(74) X_(146)
X_(75) X_(192)
X_(76) X_(194)
X_(86) X_(1654)
X_(113) X_(74)
X_(114) X_(98)
X_(115) X_(99)
X_(116) X_(101)
X_(117) X_(102)
X_(118) X_(103)
X_(119) X_(104)
X_(120) X_(105)
X_(121) X_(106)
X_(122) X_(107)
X_(123) X_(108)
X_(124) X_(109)
X_(125) X_(110)
X_(126) X_(111)
X_(127) X_(112)
X_(128) X_(1141)
X_(129) X_(1298)
X_(130) X_(1303)
X_(131) X_(1300)
X_(132) X_(1297)
X_(133) X_(1294)
X_(136) X_(925)
X_(137) X_(930)
X_(140) X_5
X_(141) X_6
X_(142) X_9
X_(618) X_(13)
X_(619) X_(14)
X_(623) X_(15)
X_(624) X_(16)
X_(629) X_(17)
X_(630) X_(18)
X_(1125) X_(10)

See also

Complement

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References

Kimberling, C. "Triangle Centers and Central Triangles." Congr. Numer. 129, 1-295, 1998.

Referenced on Wolfram|Alpha

Anticomplement

Cite this as:

Weisstein, Eric W. "Anticomplement." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Anticomplement.html

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