This is a question from calculus 3 class.

"Find the dot product of the vectors and the cosine of the angle between them."

u=i- 3j+ 7k

v= 8i- 2j- 2k

Okay, I get what to do, and I get answers but apparently they're wrong according to the back of the book. What am I doing wrong?

My work:

udotv= (1*8) + (-3*-2) + (7*-2) =28= dot product

||u|| = sqrt(1^2 + (-3)^2 + 7^2) = sqrt(59)

||v|| = sqrt(8^2 + (-2)^2 + (-2)^2) = 6*sqrt(2)

(28) / ( sqrt(59) * (6*sqrt(2)) ) = .429601

cos^-1 (.429601) =1.12675 radians= angle

Edit: The book says the dot product is 0 and the angle is also 0.