# Math Help - Vector

1. ## Vector

Find the angle formed when [4,4,2] and [4,3,12] are placed tail to tail ; then find the components of the vector that results when [4,3,12] is projected onto [4,4,2].

My answer is 48.189 for the angle.

101 = 169 + 36 - 2X13X6Xcos a
cos a = 0.666666667
a=48.189

Is it correct?

For the second part, I am not sure what it means to project a vector onto another one.

Thanks.

2. ## Re: Vector

Originally Posted by Veronica1999
Find the angle formed when [4,4,2] and [4,3,12] are placed tail to tail ; then find the components of the vector that results when [4,3,12] is projected onto [4,4,2].

My answer is 48.189 for the angle.

For the second part, I am not sure what it means to project a vector onto another one.
If $\vec{P}~\&~\vec{Q}$ are vectors then the projection of $\vec{P}\text{ onto }\vec{Q}$ is
$\text{proj}_{\vec{Q}} \vec{P} = \frac{{\vec{P} \cdot \vec{Q}}}{{\vec{Q} \cdot \vec{Q}}}\vec{Q}$