Answer:
Remember the triangular inequality says that if u and v are vectors then
[tex]\lvert\lvert u + v \lvert\lvert \leq \lvert\lvert u \lvert\lvert +\lvert\lvert v\lvert\lvert[/tex]
Since the magnitude always is a nonnegative number and the magnitude of u is 5 units and the magnitude of v is 4 units ,
[tex]0\leq \lvert\lvert u + v\lvert\lvert \leq \lvert\lvert u \lvert\lvert + \lvert\lvert v\lvert\lvert = 5+ 4 =9[/tex]
Then possibles values for the magnitude of u +v are in the interval [tex][0,9][/tex]
