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anonymous

  • one year ago

THREE QUESTIONS HELP GIVING MEDALS 1.) Let u = <5, 6>, v = <-2, -6>. Find -2u + 5v. <-20, -42> <-20, 0> <0, 18> <-6, 0> 2.) Find the dot product, a · b. a = 6i + 5j, b = -5i + 4j 50 <1, 9> -10 <-30, 20> 3.) Determine whether the vectors u and v are parallel, orthogonal, or neither. u = <7, 2>, v = <21, 6> Neither Orthogonal Parallel None of these

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  1. anonymous
    • one year ago
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    @DanJS

  2. anonymous
    • one year ago
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    @Loser66

  3. DanJS
    • one year ago
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    yeah

  4. DanJS
    • one year ago
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    You can add similar dimensions for vectors, and you can multiply a vector by a constant scalar....

  5. anonymous
    • one year ago
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    @SolomonZelman

  6. DanJS
    • one year ago
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    c*<x,y> = <cx, cy>

  7. DanJS
    • one year ago
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    <a,b> + <c,d> = <a+c , b+d>

  8. DanJS
    • one year ago
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    those are the two rules for part 1

  9. anonymous
    • one year ago
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    i literally hv no clue how to get an answer

  10. DanJS
    • one year ago
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    ok.. , here is the first step, replacing u and v with the vectors given -2u + 5v = -2*<5, 6> + 5*<-2, -6>

  11. DanJS
    • one year ago
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    Now you can, by the first rule i gave, distribute the numbers into the vectors...

  12. anonymous
    • one year ago
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    is it A?

  13. DanJS
    • one year ago
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    havent looked at answers , not sure

  14. DanJS
    • one year ago
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    -2u + 5v = -2*<5, 6> + 5*<-2, -6> = <-10, -12> + < -10, -30>

  15. DanJS
    • one year ago
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    now use rule 2 that i gave

  16. DanJS
    • one year ago
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    <-10, -12> + < -10, -30> = <-10+(-10) , -12 + (-30) >

  17. Loser66
    • one year ago
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    @em2000 It is not hard, please learn how to solve it rather than rely on others. Follow @DanJS and you can do whatever you like. Please, don't just guess the answer. YOu CAN do it by yourself.:)

  18. anonymous
    • one year ago
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    thank u @DanJS

  19. anonymous
    • one year ago
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    for #2 i got 50 and #3 i got neither, did u get those?

  20. DanJS
    • one year ago
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    2-dimensional dot product for part 2 a = <6 , 5> b = <-5 , 4> a * b = 6*-5 + 5*4 Dot product, just add the product of each dimension

  21. anonymous
    • one year ago
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    -10?

  22. DanJS
    • one year ago
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    right

  23. anonymous
    • one year ago
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    awesome, is 3 wrong?

  24. DanJS
    • one year ago
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    For part 3, the notes to remember are, if for 2 vectors A and B A * B = 0 They are Orthogonal One is a scalar multiple of the other, they are parallel, B = k*A or A = k*B

  25. anonymous
    • one year ago
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    so they def not orthogonal

  26. DanJS
    • one year ago
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    hint, the dot product is not zero, and try multiplying the first vector by 3

  27. anonymous
    • one year ago
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    ohhh theyre parallel!!

  28. DanJS
    • one year ago
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    yep

  29. anonymous
    • one year ago
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    thank u so much you are great!!!

  30. DanJS
    • one year ago
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    no prob, numbers are meaningless, just remember the 3 or 4 rules... good luck

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