Three vectors A→ , B→ and C→ satisfy the relation A→.B→ = 0 and A→.C→ = 0. The vector A→ is parallel to
B →
C→
B→ ×C→
B→ +C→
If A→ .B→ = 0, A→ is perpendicular to B.→
If A→ .C→ = 0, A→ is perpendicular to C.→
So A→ is perpendicular to both B→ and C→.
Also B→ ×C→ is perpendicular to both B → and C→
Hence A→ is parallel to B→ × C→.