−−→OA=→a and M is the foot of perpendicular on OB.
The scalar component of →a along →b=OM
=∣∣→a∣∣cosθ
=→a.→b∣∣∣→b∣∣∣
The scalar component of →a perpendicular to →b=AM
=∣∣→a∣∣sinθ
=∣∣∣→a×→b∣∣∣∣∣∣→b∣∣∣
The vector component of →a along →b=−−→OM
=OM→b∣∣∣→b∣∣∣
=(→a.→b)→b→b.→b
The vector component of →a perpendicular to →b
⇒−−→MA=−−→OA−−−→OM
=→a−(→a.→b)→b(→b.→b)
=→b×(→a×→b)→b.→b