|u| = 3, |v| = 2, and the angle between u and v (when placed tail to tail) is 45 degrees. Find |2u| + |3v|

1 answer

Make a sketch and you will see that
if we let |2u| + |3v| = R
R^2 = 6^2 + 6^2 - 2(6)(6)cos135°
= 72 - 72(-√2/2)
= 72 + 36√2
R = √(72 + 36√2 ) = appr 11.09