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anonymous

  • 5 years ago

difference equations?

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  1. anonymous
    • 5 years ago
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    amistre...hi

  2. anonymous
    • 5 years ago
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    Step 1: What you want to do is drop the constant, the same as simply making the constant zero to get the homogeneous difference equation. Then you get a general solution to that homogenous difference equation. Step 2: Then go back and come up with a trial solution to the non-homogenous difference equation, the style of the trial solution being based on the kind of terms that are creating the non-homogeneous part (this will probably be the hardest part, so read that section of material carefully). Then put in particular values that you know solve the difference equation, specific values you got from working with the difference equation such as what xo is, what x1 is, allowing you to determine what the constants in your trial solution need to be. This gives you your particular solution. Step 3: As the last step you combine your general solution and your particular solution to get your complete solution for this specific problems, and of course verify that when applied it creates the correct values for x0, x1, .... xn. Overall you will have started with a "difference equation" expressing how to get x n+1 if you know x n, and you are ending with a formula that will calculate any x n by just knowing n. The formula allows you to calculate any x n term without working out all of the terms ahead of it.

  3. anonymous
    • 5 years ago
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  4. amistre64
    • 5 years ago
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    isnt this from yesterday :)

  5. anonymous
    • 5 years ago
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    yes need clear understanding for solutions starting with 2b

  6. anonymous
    • 5 years ago
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    I have 0,0 1, -1 2, -1.5 , 3 -1.75 4 -1.875, 5 -1.9375 6, -1.96875 for a

  7. amistre64
    • 5 years ago
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    this is on 2a right?

  8. anonymous
    • 5 years ago
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    yes

  9. anonymous
    • 5 years ago
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    you need to track these as community service hours ; )

  10. anonymous
    • 5 years ago
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    add to resume

  11. amistre64
    • 5 years ago
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    lol.... the problem or this session ;)

  12. anonymous
    • 5 years ago
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    all of your time in OS

  13. anonymous
    • 5 years ago
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    lol

  14. anonymous
    • 5 years ago
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    just realized that was a joke, lol

  15. amistre64
    • 5 years ago
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    homo diff is dropping the constant... :)

  16. amistre64
    • 5 years ago
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    what does dropping the constant do for us?

  17. anonymous
    • 5 years ago
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    gives us xsubn?

  18. amistre64
    • 5 years ago
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    the good computers are all locked away today; this one hates openstudy. small font, no formating..... just awful

  19. amistre64
    • 5 years ago
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    might go to McDs later and use the wifi.... if it aint busy/closed

  20. anonymous
    • 5 years ago
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    yeah my laptop will not let me do anything in os anymore so have to sit at desktop

  21. anonymous
    • 5 years ago
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    are you in school

  22. amistre64
    • 5 years ago
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    so if we strip the constant; we are just left with: Xn+1 = (1/2)Xn which always equals itself, so I dont quite know why wed do that....

  23. amistre64
    • 5 years ago
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    yeah, in the computer lab downstairs....

  24. anonymous
    • 5 years ago
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    are you a student

  25. amistre64
    • 5 years ago
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    yup

  26. anonymous
    • 5 years ago
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    me to and unemployed since move

  27. anonymous
    • 5 years ago
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    taught 8th grade Algebra back in SC

  28. amistre64
    • 5 years ago
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    i cant get work since I hurt my back.

  29. amistre64
    • 5 years ago
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    ima "liability"

  30. anonymous
    • 5 years ago
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    oh no sorry to hear that...ever thought about starting online tutoring business..I can help you out

  31. amistre64
    • 5 years ago
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    i thought about trying to do something like that; id be nice to have some sort of income other than PELL grant...

  32. anonymous
    • 5 years ago
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    I'm studying off loans for now ; ( that is why I have to take this extra module that has nothing to do with my program of study...technically

  33. anonymous
    • 5 years ago
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    send me your email address and I can send you a presentation I'm actually presenting on Tues. and the link to my website...I just started in March and have 3 students now but hope to advertise some more this summer...brishundra@yahoo.com

  34. amistre64
    • 5 years ago
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    So the complete solution is jsut finding an equation that will sum up all the nth terms....

  35. anonymous
    • 5 years ago
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    I have xn=(0.5)raised to n *C

  36. anonymous
    • 5 years ago
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    keep looking back at table in a and messing me up bc different ?

  37. amistre64
    • 5 years ago
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    couldnt we just solve for "Xn" and plug it in? maybe?...

  38. amistre64
    • 5 years ago
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    y = .5(0) - 1 + .5(1) - 1 +.5(2)-1 + .5(3) -1 seems to be what they are getting at.

  39. amistre64
    • 5 years ago
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    we can rearrange our equation to see it better: y - .5(0) + .5(1) + .5(n) - 1 - 1 - 1 - 1

  40. amistre64
    • 5 years ago
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    we need ".5(n)" for any given interation of n right?

  41. anonymous
    • 5 years ago
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    yes

  42. amistre64
    • 5 years ago
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    and we need -(1n) for every iteration of n right?

  43. amistre64
    • 5 years ago
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    whatis: .5(n) - (n) = ?

  44. anonymous
    • 5 years ago
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    the constant

  45. amistre64
    • 5 years ago
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    at =1 we get -1.5 right?

  46. amistre64
    • 5 years ago
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    at n=2 we get: .5(2) - (2) = -2.5 right?

  47. amistre64
    • 5 years ago
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    -1.5 maybe, gonna have to see this on a calculator.... terrible font

  48. anonymous
    • 5 years ago
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    ok

  49. amistre64
    • 5 years ago
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    whats yout table in a look like?

  50. anonymous
    • 5 years ago
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    0,0 1, -1, 2, -1.5 3, -1.75...

  51. anonymous
    • 5 years ago
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    4 -1.875 5 -1.9375 6 -1.96875

  52. amistre64
    • 5 years ago
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    i get from teh original stuff, not my stuff: 0; -1; -1.5; -1.75; -1.875...

  53. anonymous
    • 5 years ago
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    I had that when I first started this , lol

  54. anonymous
    • 5 years ago
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    but looked at xo=0 and thought I was wrong

  55. amistre64
    • 5 years ago
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    your "key returns" arent formating; they look like this:

  56. amistre64
    • 5 years ago
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    the value of X0 = 0 then it iterates from there

  57. anonymous
    • 5 years ago
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    ok so 6 -1.984375

  58. amistre64
    • 5 years ago
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    we get add ons of 1/2; 3/4; 7/8; 15/16; 31/32; 63/64; 127/128; 511/512

  59. amistre64
    • 5 years ago
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    (2^n)-1 ------ 2^n

  60. amistre64
    • 5 years ago
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    [(2^n)-1] -1 - -------- = y 2^n

  61. amistre64
    • 5 years ago
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    thats our formula/equation for this bit lol

  62. amistre64
    • 5 years ago
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    n=[1,inf]

  63. amistre64
    • 5 years ago
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    it fits right?

  64. amistre64
    • 5 years ago
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    the bottom of the fractions ar plugging away at 2^n; and the tops are following one step behind at (2^n)-1

  65. amistre64
    • 5 years ago
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    X{n+1} = (1/2) X{n} 2X{x+1} = X{n} I got no idea how they supposed to do this and come up with that lol

  66. amistre64
    • 5 years ago
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    X{n+1} 1 ----- = --- X{n} 2 <-- 2^n ? if we borrow that "n"

  67. amistre64
    • 5 years ago
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    any ideas?

  68. anonymous
    • 5 years ago
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    lost...trying something

  69. amistre64
    • 5 years ago
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    I got the right equation; just dont know how to get it from their stuff....

  70. anonymous
    • 5 years ago
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    is that for c

  71. amistre64
    • 5 years ago
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    thats for ..... D i think

  72. amistre64
    • 5 years ago
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    you got a link to the "look over this material" part of it?

  73. amistre64
    • 5 years ago
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    The style of the trial solution being based on the kind of terms that are creating the non-homogeneous part (this will probably be the hardest part, so read that section of material carefully).

  74. amistre64
    • 5 years ago
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    got 10 minutes til the college closes....

  75. amistre64
    • 5 years ago
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    and StLeo is a catholic college so that ones closed for today as well; my internets are getting scarce :)

  76. amistre64
    • 5 years ago
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    email me the "material" section: tony031172@gmail.com

  77. anonymous
    • 5 years ago
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    ok THANKS a bunch!

  78. anonymous
    • 5 years ago
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    http://www.aw-bc.com/ggts/

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