Question

if A = 2hati - 3hatj+7hatk, B = hati + 2hatj and C=hatj - hatk. Find A(BxxC)

Answer 1

Given:

A = 2hati - 3hatj+7hatk,

B = hati + 2hatj and

C=hatj - hatk

To Find:

A.(BxC)

Solution:

• A = 2i - 3j+7k,

• B = i + 2j  

• C=j - k

We know ,

• BxC = $\left[\begin{array}{ccc}i&j&k\\1&2&0\\0&1&-1\end{array}\right]$ = i ( -2 - 0 ) - j ( -1 - 0 ) + k ( 1 - 0 )

• BxC = -2i + j + k
• A.(BxC) = ( 2i -3j + 7k ).( -2i + j + k) = -4 -3 + 7 = 0

Therefore the value of A.(BxC) is 0.

Answer 2

Answer:

$= - 4 - 3 + 7 \\ = 0$