condition of orthogonality


Let two straight lines of the xy-plane have the slopes m1 and m2.  The lines are at right anglesMathworldPlanetmathPlanetmath to each other iff m1 and m2 are the opposite inversesPlanetmathPlanetmathPlanetmathPlanetmath of each other, i.e. iff (http://planetmath.org/BiconditionalMathworldPlanetmathPlanetmath)

m1m2=-1.

Example.  The lines  y=(1+2)x  and  y=(1-2)x  are at right angles to each other.

Title condition of orthogonality
Canonical name ConditionOfOrthogonality
Date of creation 2013-03-22 14:48:05
Last modified on 2013-03-22 14:48:05
Owner pahio (2872)
Last modified by pahio (2872)
Numerical id 14
Author pahio (2872)
Entry type Result
Classification msc 15A57
Classification msc 51F20
Synonym condition of perpendicularity
Related topic OrthogonalCurves
Related topic InverseNumber
Related topic OppositeNumber
Related topic NormalLine
Related topic AngleBetweenTwoLines
Related topic PerpendicularityInEuclideanPlane
Related topic Evolute2
Related topic ExampleOfFindingCatacaustic
Defines opposite inverse