Hmm... Your book and / or your instructor were supposed to have covered this material before assigning homework on it....
The "projection" of a
is defined as the vector c
that is orthogonal (perpendicular) to b
and satisfies |b|2
are orthogonal, what can you say about their dot product? What can you do with the magnitudes?
For explanations and the formulas to use, try reviewing a few online lessons, such as:
. . . . .Projection of One Vector Onto Another (lesson)
. . . . .MathWorld: Projection (article)
. . . . .Dot Products and Projections (lesson)
. . . . .The projection of a vector
. . . . .Wikipedia: Vector projection
. . . . .How to Project One Vector onto Another
. . . . .Vectors (tutorial)
Once you have learned the basic terms and techniques, please attempt the exercise. If you get stuck, you will then be able to reply with a clear listing of your steps and reasoning so far.