Question

If vector a vector b vector c are unit vectors such that vector a + vector b + vector c equal to zero vector then find the value of the state vector p + vector b into vector p + vector c into vector

Answer 1

Here × is a cross product.

(A→+B→)×(A→−B→)

=(A→×A→+B→×A→−A→×B→−B→×B→

Now A→×A→=0→ and B→×B→=0→ and A→×B→=−B→×A→

so we get (A→+B→)×(A→−B→) =B→×A→−A→×B→=2(B→×A→)