scalar projections and vector projections.

[ald942]

Okay so im really struggling with vectors in college. The thing is once i need to see how something is done.Il write out the question im having trouble with.

Find the scalar and vector projection of (B) onto (A) given that: (A) =2i +3j -4k and (B)=-i + 2j+5k


So thats the question and from my college notes im told * the scalar projection of (B) onto (A) is (A).(B) divided by |A|.

any help is greatly needed.

 

[Deleted member 4993]

Okay so im really struggling with vectors in college. The thing is once i need to see how something is done.Il write out the question im having trouble with.

Find the scalar and vector projection of (B) onto (A) given that: (A) =2i +3j -4k and (B)=-i + 2j+5k


So thats the question and from my college notes im told * the scalar projection of (B) onto (A) is (A).(B) divided by |A|.

any help is greatly needed.

A = a[sub:2eolt3a0]1[/sub:2eolt3a0]i + a[sub:2eolt3a0]2[/sub:2eolt3a0]j + a[sub:2eolt3a0]3[/sub:2eolt3a0]k

B = b[sub:2eolt3a0]1[/sub:2eolt3a0]i + b[sub:2eolt3a0]2[/sub:2eolt3a0]j + b[sub:2eolt3a0]3[/sub:2eolt3a0]k

then

\(\displaystyle A\cdot B = a_1b_1 + a_2b_2 + a_3b_3\)

and

\(\displaystyle |A| = \sqrt{a_1^2 + a_2^2 + a_3^2\)

Now proceed....