Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

spndsh

  • 2 years ago

Simplify: Using Vector Algebra: 1/2 (a +b) dot [c cross (2a +b)]

  • This Question is Closed
  1. spndsh
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1355251229553:dw|

  2. spndsh
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    do i distribute the 1/2 or the (a+b)?

  3. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    if i remember properly, cX(a.b) is the scalar triple product or box product denoted by [a b c] ans a. [a b c] = b. [a b c] = c. [a b c] = 0 so if u distribute (a+b), you'll get final answer as 0

  4. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    also [na mb pc] = mnp [a b c ]

  5. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    *and

  6. spndsh
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so i wouldn't simplify the inside of the brackets?

  7. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    [cX 2a.b] = 2 [a b c]

  8. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    i think i mis-interpreted the question....

  9. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1355252100635:dw|

  10. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    =0 + 1/2 [a c b]+ 1/2 b . 2c X a + 1/2 b . c X b =0 + 1/2 [a c b]+1/2 [b c a]+ 1/2[b c b] =0 -1/2 [a b c] +1/2 [a b c] + 0 =0+0+0=0 now this seems right.

  11. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    if you could understand.... ask if there is any doubt in any step.

  12. spndsh
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    just one question whats the operation inside the bracket i.e [b c a]?

  13. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    cyclic change doesn't change sign [a b c] = [b c a] = [c a b] else, sign changes [a b c] = -[a c b ] = -[b a c]

  14. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    if any 2 or more vectors are same, then box product =0 [a a b] = [b b a] = ... = 0

  15. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    or u meant to ask [a b c] = a.bXc ?

  16. spndsh
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

  17. spndsh
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    thanks so much!

  18. hartnn
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    hmm...welcome ^_^

  19. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.