यदि ` veca , vecb , vecc` मात्रक सदिश इस प्रकार है कि ` veca + vecb + vecc = vec0` तो ` veca "." vecb + vecb "." vecc"." vecc "." veca ` का मान ज्ञात कीजिए ।

Explanation

` veca , vecb ` और ` vecc ` एकांक सदिश है
` therefore | veca| = | vecb| = | vecc| =1`
और ` veca + vecb+ vecc = vec0`
` implies ( veca + vecb + vecc) . ( veca + vecb + vecc ) = vec0`
` implies ( veca + vecb + vecc) .( veca + vecb + vecc ) = vec0 . vec0`
`implies | veca| ^(2) +| vecb|^(2) +| vecc|^(2) + 2 ( veca "." vecb + vecc)= vec0 ."" vec0`
`implies | veca | ^(2) + | vecb | ^(2) + | vecc|^(2) + 2 ( veca "." vecb" ." vecb"." vecc + vecc"." veca ) =0`
` implies 1+1+1+2( veca "." vecb + vecb "+" vecb "." vecc + vecc"." veca )=0`
`implies veca "." vecb + vecb ."" vecc +vecc ."" veca =-(3)/(2)`