Calculate the angle between u = [5,7,-1] and v = [8,7,8]

Answer 1

For any two vectors u and v
u.v = |u| |v|cosØ, where Ø is the angle between them
40 + 49 - 8 = √(25+49+1)√(64+49+64)cosØ
81 = √75√177 cosØ
cos Ø = .70302
Ø = 45.33°

Answer 2

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