Question

If A= 2 i + 3 j+ k and B = 3 i+2j+4 k then,
find the value of (A+B)*(A-B)​

Answer 1

Explanation:

A = 2 i + 3 j + k

B = 3 i + 2j + 4k

A + B = 5 i + 5 j + 5 k

A - B = -i + j - 3 k

(A + B)*(A - B)

(5i + 5j + 5k)*(-i + j -3k)

5(-1)+5(1)+5(-3)

-5 + 5 -15

-15