North is the direction of positive y-axis. East is the direction of positive x-axis. So West will be the direction of negative x-axis.
Northwest will mean, in between north and west i.e. in between y-axis and the negative x-axis which is the mid of the 2nd quadrant. Thus the vector pointing northwest will form an angle of 135 degrees with positive x-axis.
The magnitude of unit vector is 1 and is forming an angle of 135 degrees. In terms of its components, we can write:
x-component = 1 cos (135) =

y-component = 1 sin (135) =

Thus the unit vector will be =

In vector form, component form the vector can be written as:
