Find the angle between the given vectors to the nearest tent

Find the angle between the given vectors, to the nearest tenth of a degree. u =(-5,1) , v = (-2,5)

A.) 56.9 degrees

B.) 259.5 degrees

C.) 33.1 degrees

D.) 79.5 degrees

Solution

cos(theta) = u.v/|u||v| = (-5i + j).(-2i + 5j)/[sqrt(26) x sqrt(29)]

cos(theta) = 15/sqrt(26 x 29) = 0.5462

=> theta = 56.9 degree