Given |u| = 1 and a = 45, you can determine the component form of u.
[tex]u = \ \textless \ cos(45),sin(45)\ \textgreater \ [/tex]
In same way you can find component form of u+v
[tex]u+v = \ \textless \ 2cos(90), 2sin(90)\ \textgreater \ [/tex]
By property of vector subtraction:
v = (u+v) - u
[tex]v = \ \textless \ 2cos(90) - cos(45), 2sin(90) - sin(45)\ \textgreater \ [/tex]
[tex]v = \ \textless \ -\frac{\sqrt{2}}{2}, 2-\frac{\sqrt{2}}{2} \ \textgreater \ [/tex]