Three forces F1 = 3N, F2 = 5N, F3 = 6N, when their angle changes, what is the change range of their resultant force? Under what circumstances is the resultant force the smallest?

Three forces F1 = 3N, F2 = 5N, F3 = 6N, when their angle changes, what is the change range of their resultant force? Under what circumstances is the resultant force the smallest?

Variation range: 0n ≤ f (combined) ≤ 14N
When the resultant force of F1 and F2 is 6 N, the resultant force is the smallest