Three-point alignment condition using determinants

Three unaligned points on a Cartesian plane form a triangle of vertices A(x)THEyTHE), B(xByB) and C(xÇyÇ). Your area can be calculated as follows:
A = 1/2. |D|, that is, |D| / 2, considering D = .
For the area of ​​the triangle to exist, this determinant must be different from zero. If the three points, which were the vertices of the triangle, are equal to zero, they can only be aligned.
Therefore, we can conclude that three distinct points A(xTHEyTHE), B(xByB) and C(xÇyÇ) will be aligned if the determinant corresponding to them is equal to zero.
Example:
Check if the points A(0,5), B(1,3) and C(2,1) are or not collinear (they are aligned).
The determinant regarding these points is. In order for them to be collinear, the value of this determinant must equal zero.
= 10 + 1 – 6 – 5 = 9 – 6 – 5 = 5 – 5 = 0
Therefore, points A, B and C are aligned.

by Danielle de Miranda
Graduated in Mathematics
Brazil School Team

Analytical Geometry - Math - Brazil School

Source: Brazil School - https://brasilescola.uol.com.br/matematica/condicao-alinhamento-tres-pontos-utilizando-determinantes.htm

instagram story viewer
Solar and lunar eclipse

Solar and lunar eclipse

Eclipse is a phenomenonastronomical darkened total or partial of a star due to the passage of som...

read more

Origins of the Brazilian People. Brazilian people's miscegenation

THE Brazilian population is quite mixed. This was due to the mixture of different human groups th...

read more

Luddism. Ludism and English workers in the 19th century

With the advent of the Industrial Revolution in the 18th century, progressive and intense social,...

read more