The angle between vec(a) and vec(b) " is " 0^(@) then angle between 2 vec(a) and -3 vec(b) is

The angle between vec(a) and vec(b) " is " 0^(@) then angle between 2

1.	The angle between vec(a) and vec(b) " is " 0^(@) then angle between 2 vec(a) and -3 vec(b) is
Answer» `PI//3` `pi` `pi//6` NONE of these Answer :B