The value of `hati xx(hatixxa)+hatjxx(hatjxxa) +hatk xx(hatkxxa)` is

Options

A. a
B. `axxhatk`
C. `-2a`
D. `-a`

Answer

C

Explanation

(c ) Suppose `a=a_(1)hati+a_(2)hatj+a_(3)hatk`
`Now, (hatixxa) =a_(2)hatk-a_(3)hatj`
`Now ,hatixx(hatixxa)=-a_(2)hatj-a_(3)hatk`
`"similarly" ,hatjxx(hatjxxhata)=-a_(1)hati-a_(3)hatk`
` and hatkxx(hatjxxa) =-a_(1)hati-a_(2)hatj`
`therefore hati(hatixxa)+hatj(hatjxxa)+hatk(hatkxxa)=-2a`