Question:
Three vectors A, B, and C add up to zero. Find which is false
(a) vector (A×B)C is not zero unless vectors B, C are parallel
(d) vector (A×B).C is not zero unless vectors B, C are parallel
(c) if vectors A, B, C define a plane, (A×B)C is in that plane
(d) (A×B).C = $|A||B||C|$ such that $\mathrm{C}^{2}=\mathrm{A}^{2}+\mathrm{B}^{2}$
Solution:
The correct answer is c) if vectors A, B, C define a plane, $(A \times B) C$ is in that plane and d) $(A \times B) . C=$ $|A \| B||C|$ such that $\mathrm{C}^{2}=\mathrm{A}^{2}+\mathrm{B}^{2}$