If a→,b→ and c→  are non-coplanar vectors a→×c→ is perpendicular to a→×(b→×c→)  then the value of [a→×(b→×c→)]×c→ is equal to

Given that   a→,b→ and c→  are non-coplanar vectors  Thus, [a→b→c→]≠0----iagain a→×(b→×c→)⋅(a→×c→)=0or  [(a→⋅c→)b→−(a→⋅b→)c→]⋅(a→×c→)=0or  (a→⋅c→)[b→a→c→]=0or  (a→⋅c→)=0 Hence, a→ and c→ are perpendicular. ---iia→×(b→×c→)=(a→⋅c→)b→−(a→⋅b→)c→or   [a→×(b→×c→)]×c→=0→