Difference between revisions of "CrossRatio Command"
From GeoGebra Manual
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; CrossRatio[ <small><</small>Point A<small>></small>, <small><</small>Point B<small>></small>, <small><</small>Point C<small>></small>, <small><</small>Point D<small>></small> ]:Calculates the cross ratio ''λ'' of four collinear points ''A'', ''B'', ''C'' and ''D'', where:<br>''λ = [[AffineRatio Command|AffineRatio[B, C, D]]] / [[AffineRatio Command|AffineRatio[A, C, D]]].'' | ; CrossRatio[ <small><</small>Point A<small>></small>, <small><</small>Point B<small>></small>, <small><</small>Point C<small>></small>, <small><</small>Point D<small>></small> ]:Calculates the cross ratio ''λ'' of four collinear points ''A'', ''B'', ''C'' and ''D'', where:<br>''λ = [[AffineRatio Command|AffineRatio[B, C, D]]] / [[AffineRatio Command|AffineRatio[A, C, D]]].'' | ||
:{{example|1=<div><code><nowiki>CrossRatio[(-1, 1), (1, 1), (3, 1), (4, 1)]</nowiki></code> yields ''1.2''</div>}} | :{{example|1=<div><code><nowiki>CrossRatio[(-1, 1), (1, 1), (3, 1), (4, 1)]</nowiki></code> yields ''1.2''</div>}} | ||
Revision as of 10:51, 20 August 2015
- CrossRatio[ <Point A>, <Point B>, <Point C>, <Point D> ]
- Calculates the cross ratio λ of four collinear points A, B, C and D, where:
λ = AffineRatio[B, C, D] / AffineRatio[A, C, D]. - Example:
CrossRatio[(-1, 1), (1, 1), (3, 1), (4, 1)]yields 1.2
