If F_B = 2kN and the resultant force acts along the positive u axis, determine the magnitude of the resultant force and the angle u.
Let us first draw the vector components as follows:
Notice that the resultant is along the u-axis as stated by the question.
Now, we will draw the vector components tail to tail as follows:
We can now use law of sines to figure out \phi. (Forgot the law of sines?)
From this, we can figure out \theta.
\theta = 78.59^0