Just as you can enter a number by giving an equation that reduces to it, WeBWorK allows you to enter points and vectors by giving equations for the individual coordinates, or by using a vector-valued equation that reduces to your answer. For example,
<1-(-3),2-sqrt(4),6/2> and [1-(-3)]i + [2-sqrt(4)]j + (6/2)k
both represent the vector 4,0,3, while <1,0,-1> + <2,-2,3> could be used to answer a question that asks for the vector 3,2,2.