Given 3 vectors: A = 4k B = 8i + k C = 3i - 4j then C(A • B) =_______?
The answer should be 13 but the way I'm doing it must be wrong because gives me another number. Please show your work so I can see what I'm missing. Thanks :)
- ?Lv 78 years agoFavorite Answer
A = 4k = 0i + 0j + 4k
B = 8i + k = 8i + 0j + k
C = 3i - 4j = 3i - 4j + 0k
Now, (A • B) = (0*8 + 0*0 + 4*1) = 4 --- a scalar quantity
C(A • B) = (3i - 4j + 0k)*4 = (12i - 16j + 0k) = (12i - 16j) ---- a vector quantity
If you want the magnitude of C(A • B)
it is given by | C(A • B) | = | (12i - 16j) | = √(12² + 16²) = 20
How the answer is 13, I am also not able to understand.
If your question is something else write it as it is without modifying.
- gaddLv 44 years ago
The gist of the communicate accessible (sorry, there are too many pages to furnish each and all the links) is that wands help to concentration the magic resident interior the witch or wizard, yet wandless magic remains achievable, quite for terribly proficient people like Snape and Dumbledore. some examples ... Apparition Assuming one's Animagus style (or Metamorphpagus) Accio (the Summoning attraction) Elves can do magic without utilising wands Lumos