A vector a and B, if a & # 178; = B & # 178;, then a = B or a = - B The answer is wrong, but I don't know why,

A vector a and B, if a & # 178; = B & # 178;, then a = B or a = - B The answer is wrong, but I don't know why,

The definition of vector is a quantity with both direction and size, that is, vector; a = - B = b = - 178; only represents the size of vector, that is, a = B, does not represent direction; a = B represents the quantity with the same direction and the same size; a = - B represents the quantity with the opposite direction but the same size; two quantities with the same size but a certain angle (not including