Question about vectors?

given u = %26lt; 1,2,-3%26gt; and v = %26lt;-1,b,0%26gt; find the following the answers will be on tems of b.


a) w= PROJvU


b) w= PROJuV


c) the angle between u and v


I don't find the way to solve this problem I will apreciate any help. thanks.

Question about vectors?
The projection of a vector a onto a vector u is





[(a dot u) / |u|^2] multiplied by u





The angle between two vectors u and v, theta, is





u dot v = |u| |v| cos(theta)