Practice problem asks for the component of vector A=(2,1,-4) in the direction of B=(1,2,3).
I've found the direction vector of B (by dividing B by its length of √14). Let's call this direction vector d.
Now, is the dot product (x.d) the answer?
I found -8/√14
Opalg, many books use the opposite convention- that the "component" of a vector in a given direction is a scalar. For example, the "component" of <a, b, c> in the <1, 0, 0> direction is "a", not <a, 0, 0>. keysar7, better check your textbook or with your teacher to be sure which convention is being used.