Question

Vectors,

Can you please help me out with this ?


http://screencast.com/t/SfudfuCS

Answer 1

okie do you know dot product of vectors??

Answer 2

dot product of two vectors is defined as

\[vector(A).vector(B)=|vectorA| \times |vectorB| \times \cos \theta\]

now we can write above equation as follows

\[\cos \theta =vector(A).vector(B)/|vectorA| \times |vectorB|\]
that is
\[\theta =\cos^{-1}[vector(A).vector(B)/|vectorA| \times |vectorB| ]\]

that is theta =cos^-1[dot product of vectors A and B / product of magnitude of vectors A and B]

Answer 3

now just put values and get angle theta..

Answer 4

@Christos