ABCD-parallelogram. Find the length of the AC vector if the vector BA = (0; 2; 3) and the vector BD = (1; 4; 5).
Since ABCD is a parallelogram, the vectors lying on its opposite sides are collinear, that is, they are equal in absolute value. To find the length of the vector AC, it is necessary to express the coordinates of this vector in terms of the coordinates of other vectors. The AC vector is equal to the sum of the AD and DC vectors. Vector AD is equal to the difference between vectors BD and BA. It turns out that the vector AC is equal to the sum of the vectors AD and DC or the difference of the vectors AD and BA. It is known from the problem statement that the vector BA = (0; 2; 3), and the vector BD = (1; 4; 5), then the vector AC = (1; 4; 5) – (0; 2; 3) – ( 0; 2; 3); AC = (1; 0; – 1). The length of the vector AC is found by the formula | AC | = √ (x ^ 2 + y ^ 2 + z ^ 2); | AU | = √ (1 ^ 2 + 0 ^ 2 + (- 1) ^ 2); | AU | = √2.
Answer: the length of the AC vector is √2.