Resolved part of vector a→ and along vector b→ is   a1→ and at perpendicular to b→ is a→2, then a→1×a→2 is equal to

a→1=(a→⋅b^)b^=(a→⋅b→)b→|b→|2⇒a→2=a→−a→1=a→−(a→⋅b→)b→|b→|2 Thus, a→1×a→2=(a→⋅b→)b→|b→|2×a→−(a→⋅b→)b→|b→|2=(a→⋅b→)(b→×a→)|b→|2