Differential Equations - I need Help

This is a discussion on Differential Equations - I need Help within the A Brief History of Cprogramming.com forums, part of the Community Boards category; Okay here's a few problems that i've solved, i just need some math wiz to check me on my work. ...

  1. #1
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    Differential Equations - No more help, I FIGURED OUT THE MISTAKES WOOH

    Okay here's a few problems that i've solved, i just need some math wiz to check me on my work. Thanks a lot guys, i really appreciate it!

    1. y''' - 4y'' + y' + 6y =0
    ANSWER: y=(c1)e^(3X) + (c2)e^(2X) + (c3)e^(-X)

    2. 4y''' + 28'' + 61y' + 37y =0
    ANSWER: y=(c1)e^(-X) + (c2)e^(-3X)(cos0.5X) + (c3)e^(-3X)(sin0.5X)

    3.y'''' - 2y''' + 2y'' -2y' + y =0
    ANSWER: y=((c1) + c(2)X)e^X + (c3)e^X(cosX) + (c4)e^X(sinX)

    4. 4y''''' - 23 y'''' -33y'' - 17y' - 3y =0
    ANSWER: y=(c1)e^(3X) + ((c2) + (c3)X)e^(-X) + ((c4) + (c5)X)e^(-0.5X)

    FOR # 5/6 I USED METHOD OF UNDETERMINED COEFIFICENTS FOR NONHOMOGENEOUS DIFF EQ'S

    5.y'' - 3y' - 4y = 2sinX
    ANSWER: y=(c1)e^(4X) + (c2)e^(-X) + (3/17)cosX - (5/17)sinX

    6.y'' - 3y' -4y = 4X^2
    ANSWER: y= (c1)e^(4X) + (c2)e^(-X) - (1/8) - (1/4)X^2
    Last edited by KneeGrow; 03-28-2004 at 09:09 PM.

  2. #2
    Intranasal Heroin User Xterria's Avatar
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    I hope i never have to do math that hard...

  3. #3
    Registered User axon's Avatar
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    >>I hope i never have to do math that hard...

    well if you are going into ANY engineering field you will have to leardn DFQ. KneeGrow, I'll check it out later tonite if I get some spare time.

  4. #4
    Intranasal Heroin User Xterria's Avatar
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    -DAAWEETED!!!!!!-
    Last edited by Xterria; 03-28-2004 at 08:31 PM.

  5. #5
    ¡Amo fútbol!
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    You are a loser.

  6. #6
    Intranasal Heroin User Xterria's Avatar
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    huh? what'd i do now?
    EDIT
    alright i get it..
    ..i guess ill delete it
    Last edited by Xterria; 03-28-2004 at 08:31 PM.

  7. #7
    Registered User axon's Avatar
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    I obviously missed something

    some entropy with that sink? entropysink.com

    there are two cardinal sins from which all others spring: Impatience and Laziness. - franz kafka

  8. #8
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    Ahh someone please check those answers the first four are so easy just check for the roots then do e^x but i need someone to check 5 + 6

    Thanks a lot

  9. #9
    Registered User Aran's Avatar
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    agh.... type in sentences please

    I only WISH i could do those problems. I guess you just aren't an english person.

    [half j/k]
    And, also, your cheap attempt at making it look like you have 4000 something posts is, at the very least, laughable and embarassing. Embarassing not only to you, but to all of mankind (for harboring such rabid stupidity!).
    [/half j/k]
    Last edited by Aran; 03-28-2004 at 10:12 PM.

  10. #10
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    Okay whatever ya'll can stop posting on this thread as i have figured out all the answers Thanks to all that helped = 0 people lol? Anyways whatever

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