 Hi, and welcome to our session. Let us discuss the following question. The question says, with the vectors a i cap plus a j cap plus c k cap, i cap plus k cap, and c i cap plus c j cap plus b k cap, the coplayer showed that c squared is equal to a v. Now we begin with the solution, let vector a 1 is equal to a i cap plus a j cap plus c k cap, vector a 2 is equal to i cap plus k cap, and vector a 3 is equal to c i cap plus c j cap plus b k cap. We note that 3 vectors vector a vector b and vector c coplayer only if vector a dot vector b cross vector c is equal to 0. Coplayer if vector a 3 is into determinant of 0 1 c v minus a into determinant of 1 1 c v plus c into determinant of 1 0 c c is equal to 0. This implies a into 0 minus c minus a into b minus c plus c into c minus 0 is equal to 0. This implies minus a c minus a v plus a c plus c squared is equal to 0. Now plus a c and minus a c cancels out, so we are left with minus a v plus c squared equals to 0 and this implies c squared is equal to a v. Hence we prove that if vectors a 1, a 2 and a 3 are coplayer and c squared is equal to a v. So this completes the session. Bye and take care.