Question

Prove that `hati xx(vecaxxveci)+hatjxx(vecaxxvecj)+hatkxx(vecaxxveck)=2veca`

Answer 1

`hatixx(veca xxhati)=(hati.hati)veca-(veca.veci)=veca-(veca.veci)hati`
`hatjxx(vecaxxhatj)=veca-(veca.hatj)and hatkxx(vecaxxhatk)veca-(veca.hatk)hatk`.
`hatixx(vecaxxhati)+hatjxx(vecaxxhatj)+hatkxx(vecaxxhatk)=3veca-((veca.hati)hati+(veca.hatj)+(vecaxx hatk)hatk)=2veca`