If ab → = a →, ad → = B →, then OC →= Ab →, DC →, a →, B → and so on are vectors

If ab → = a →, ad → = B →, then OC →= Ab →, DC →, a →, B → and so on are vectors

∵AB→=2DC→
∴AB‖DC,AB=2DC
∴△OCD∽△OAB
That is, the vector OC = 1 / 3 vector AC
Vector AC = ad → + DC → = B → + a → / 2
∴OC→=b→/3+a→/6