यदि `vec(a)=vec(i)=2 vec(j)-3 vec(k), vec(b)=2 vec(i)+vec(j)-vec(k)` तथा `vec(c)=vec(i)+3 vec(j)-2vec(k)` तो `vec(a)xx ( vec(b)xx vec(c))` का मान निकालें ।

Answer

`-hat(i)-8 hat(j)+5 hat(k)`