Hello,

(see picture)

could you explain which is correct way to transform first expression into vectors (a or b) and why?

http://imageshack.com/a/img849/4557/qrrh.png

Thank you

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- Feb 13th 2014, 11:15 AMNewRA simple question about vectors
Hello,

(see picture)

could you explain which is correct way to transform first expression into vectors (a or b) and why?

http://imageshack.com/a/img849/4557/qrrh.png

Thank you - Feb 13th 2014, 01:45 PMemakarovRe: A simple question about vectors
If is the vector from to whose length is 1, then the correct expression is (b). This is because is the angle between and , and is the angle between (plotted from ) and , so and . Dot product uses the angle between the two vectors. If the length of is not 1, then one has to divide by (in addition to the division by ).

- Feb 14th 2014, 09:53 AMHartlwRe: A simple question about vectors
None of the expressions are vectors???