20 12 Guangdong college entrance examination liberal arts mathematics third question to find vector AC. Solution of vector AC: "Isn't the back coordinate subtracted from the front coordinate?" If not, when? ... ∫ vector AB=( 1, 2), BC=(3, 4)

∴ Vector AC= Vector AB+BC = (1+3,2+4) = (4,6)

Option a

Vector AC solution: when a and c coordinates are known, subtract a coordinate from c coordinate;

This problem is known, vector AB=( 1, 2), BC=(3, 4) to find vector AC.

You have to use the method of vector synthesis, and pay attention to the direction of vectors when solving problems.

Vector AC= vector AB+BC