Question

In sistemul de coordonate xOy se cnsidera punctele A,B,C astfel incat A(1,3),B(2,5) si AC (vector)=2*AB(vector).Sa se determine coordonatele punctului C.

Answer 1

In baza {i, j}, vectorii se exprima asa:
AC = ( x C - 1)i + (y C - 3)j;
AB = ( 2 -1)i + (5 - 3)j = 1i + 2j
AC (vector)=2*AB(vector) => x C - 1 = 1 si y C - 3 = 2 => x C = 2 si y C = 5 => C(2;5).


Bafta!