∑H = Sum of horizontal component
∑V = Sum of vertical component
First
∑H = 20 cos α + 20 cos(360° – β)
∑H = 20 cos α – 20 cos β ...(i)
Now
∑V = 20 sinα + 20 sin(3600 – β)
–50 = –50 + 20 sin α + 20 sin β ...(ii)
Hence the resultant of the system = R = (∑H2 + ∑V2)1/2
Let additional single force be ‘R’ and its magnitude is equal to
R’ = R = [(20 cosα – 20 cosβ)2 + (–50 + 20 sinα + 20 sinβ)2]1/2
This force should act in direction opposite to the direction of force ‘R’