Question

For any non-zero vectors a and b, [b a × b a] = ?

Options

• a × b

• |a × b|²

• 0

• |a × b|

Answer 1

|a × b|² 

Explanation:

We have,

[b a × b a]

= [a × b a b]   ....[∵ [a b c] = [b c a] = [c a b]]

= (a × b) · (a × b)

= (a × b)²

= |a × b|²