Question

Can any show me how to find the angle between the two vectors (-7,1,1) and (3,2,-2)

Answer 1

you will need 3 things; at least ....

the dot product, and the length of each vector

Answer 2

\[cos(\alpha)=\frac{a\cdot b}{|a|~|b|}\]
\[\alpha=cos^{-1}\left(\frac{a\cdot b}{|a|~|b|}\right)\]