Question

The value of `hati(hatj + hatk)hatj * (hati + hatk) + hatk - (hati + hatj)` is-

विकल्प

• 0

• –1

• 1

• 3

Answer 1

1

Explanation:

`|hati, hatj, hatk|` are the perpendicular unit vectors, we know,

∴ `hati xx hatj = hatk, hatj, hatk = hati, hatk xx hati = hatj`

And `hati * hatj` = 1, `hatj * hatj` = 1 and `hatk * hatk` = 1

⇒ `hati * (hatj xx hatk) + hatj * (hati xx hatk) + hatk * (hati * hatj)`

= `hati * (hatj xx hatk) - hatj * (hatk xx hati) + hatk * (hati xx hatj)` .......`[because hati xx hatk = - hatk xx hati]`

= `hati * hati - hatj * hatj + hatk * hatk`

= 1 + 1 + 1

= 1