Question

Let the vectors `veca` and `vecb` be such that `|veca| = 3` and `|vecb| = sqrt2/3`, then `veca xx vecb` is a unit vector, if the angle between `veca` and `vecb` is ______.

विकल्प

• `pi/6`

• `pi/4`

• `pi/3`

• `pi/2`

Answer 1

Let the vectors `veca` and `vecb` be such that `|veca| = 3` and `|vecb| = sqrt2/3`, then `veca xx vecb` is a unit vector, if the angle between `veca` and `vecb` is `underline(pi/4)`

Explanation:

`|veca| = 3, |vecb| = sqrt2/3`

`|veca xx vecb| = 1`

`|veca||vecb||sinthetahatn| = 1`

`|veca||vecb||sintheta| = 1`

`3 xx sqrt2/2 xx sintheta = 1`

`sintheta = 1/sqrt2`

`theta = pi/4`

The correct option is `pi/4`.