Dalia S.

asked • 10/20/14

Perform the following operations on the vectors

Perform the following operations on the vectors vec{u} =<4,-4,4>, vec{v}=<4,2,-4>, and vec{w} =<0,-2,-1>.

(u)•vec(w)=

(u•v)u=

((w•w)u)•u=

u•v+v•w=

1 Expert Answer

By:

Byron S. answered • 10/20/14

Math and Science Tutor with an Engineering Background

Dalia S.

thank you for the help, i got a the above questions except for this one ((w•w)u)•u
when i did the calculations i got <80,-80,80> as a vector
 
 
Report

10/20/14

Byron S.

tutor
Let's see.. w·w is 02 + (-2)2 + (-1)2 = 5
5u = <20, -20, 20>
(5u)·u = 20*4 + -20*-4 + 20*4 = 80
Don't forget that a dot product is the sum of the products!
Report

10/20/14

Byron S.

tutor
Sorry, sign errors, that should be 240, not 80!
Report

10/20/14

Dalia S.

ohhh ok, my mistake was that i forgot to add the dot products at the end, thank you for your help! 
Report

10/20/14

Byron S.

tutor
Your middle term should also be (-20)*(-4) = +80, not -80. (I did the same thing while multiplying in my head.) Otherwise, you're in good shape!
Report

10/20/14

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.