If a→=i^+j^,b→=j^+k^,c→=k^+i^ then in the reciprocal system of vectors a→,b→,c→ reciprocal of vector a→is
i^+j^+k^2
i^-j^+k^2
-i^-j^+k^2
i^+j^-k^2
a′→=b→×c→[a→b→c→]=i^+j^−k^2