The DW Math Thread

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  • buffnab
    buffnab Posts: 1 Arc User
    edited October 2012
    Muslims invented math.
  • CeliaZ - Sanctuary
    CeliaZ - Sanctuary Posts: 901 Arc User
    edited October 2012
    Mooooooooo - Lost City wrote: »
    speed of the fly is S. What you care about is the fraction of the rope the fly moves across rather than some absolute distance. For example, when the rope is scretched to 2m, it would be as if the fly is moving at speed of 1/2 * S.

    so this "speed" decreases with respect to time S' = 1/t * S, where t starts at 1. So you integrate 1/t * S with respect to t, from 1 to x, so that it will sum to 1m (meaning distance of 1 original rope length). Solving for x gives you that formula.

    Thanks alot, that was indeed the differential equation I couldnt come up with.
    [SIGPIC][/SIGPIC]
  • foodgasm
    foodgasm Posts: 4 Arc User
    edited October 2012
    This looks like such a legit thread I made a forum account just for it o.o

    Do you provide calc help? Or rather..

    CAN YOU PLEASE HELP ME WITH MY CALC D:

    Pretty, pretty, pretty please with sugar on top? *bats eyelashes*

    Thank you b:thanks
  • Decus - Dreamweaver
    Decus - Dreamweaver Posts: 5,033 Arc User
    edited October 2012
    foodgasm wrote: »
    This looks like such a legit thread I made a forum account just for it o.o

    Do you provide calc help? Or rather..

    CAN YOU PLEASE HELP ME WITH MY CALC D:

    Pretty, pretty, pretty please with sugar on top? *bats eyelashes*

    Thank you b:thanks

    Of course, I'd be happy to!
    Proving that not only archers do math since 2009. b:victory
    Current math challenge: pwi-forum.perfectworld.com/showthread.php?t=1029711&page=45
    [SIGPIC][/SIGPIC]
    "Any skills that can be used to kill you will interrupt BB when successful." -truekossy | "...Sage archers are kind of like Mac owners. They are proud of the weirdest and most unnecessary things." -Aesthor | "We ALL know Jesus doesn't play PWI. He may have suffered a lot for humanity, but he'd NEVER punish himself this way." -Abstractive | "I approve of bananas." -SashaGray
  • foodgasm
    foodgasm Posts: 4 Arc User
    edited October 2012
    Decus - Dreamweaver wrote: »
    Of course, I'd be happy to!

    ily <3

    http://imageshack.us/a/img132/73/ermahgerd1.png

    It's the ones I highlighted with a red circle that I have no idea how to start with. b:cry

    I made some progress with the first one though but I'm kinda stuck.

    Like IxI means +ve x right? So I'd get sqrt -a(x) + b, but since it says that the limit is 0- and - indicates that you approach 0 from smaller values of 0 (i.e the -ves) does that make IxI -ve instead of +ve? @_@

    Please note that prior to this course, I had no basic understanding of limits so my base for limits isn't very strong.. YET! >:D
  • Mooooooooo - Lost City
    Mooooooooo - Lost City Posts: 377 Arc User
    edited October 2012
    foodgasm wrote: »
    ily <3

    http://imageshack.us/a/img132/73/ermahgerd1.png

    It's the ones I highlighted with a red circle that I have no idea how to start with. b:cry

    I made some progress with the first one though but I'm kinda stuck.

    Like IxI means +ve x right? So I'd get sqrt -a(x) + b, but since it says that the limit is 0- and - indicates that you approach 0 from smaller values of 0 (i.e the -ves) does that make IxI -ve instead of +ve? @_@

    Please note that prior to this course, I had no basic understanding of limits so my base for limits isn't very strong.. YET! >:D

    your teacher is weird. all of them says "this is not an easy problem. blah blah"

    top right. try factoring x - 8 as diff of cubez.

    bottom left. line from center of circle to tangent point should be perpendicular to the line.

    bottom right. simplify the top part and then just look for a pattern as you take each derivative.
    youtube channel: youtube.com/user/chezedude
  • foodgasm
    foodgasm Posts: 4 Arc User
    edited October 2012
    Mooooooooo - Lost City wrote: »
    your teacher is weird. all of them says "this is not an easy problem. blah blah"

    top right. try factoring x - 8 as diff of cubez.

    bottom left. line from center of circle to tangent point should be perpendicular to the line.

    bottom right. simplify the top part and then just look for a pattern as you take each derivative.

    Okie dokie I'll try that :) And these are all the last questions of past midterms and the prof designed it to **** you over basically. The rest of the paper is pretty straightforward plug and chug then you get to the last question and... Yeah. @_@

    Yay for being sick and calc all nighters!
  • Decus - Dreamweaver
    Decus - Dreamweaver Posts: 5,033 Arc User
    edited October 2012
    Guess I'll take the problem Cheze didn't claim. Also, I'll assume you are allowed to use L'Hopital's rule since it doesn't say you cannot.

    As it stands, the current limit is not indeterminate unless b = 3. So, let's set b = 3. Since now it would result in the form 0/0, we can take the derivative of the top and bottom. I can keep on going to solve this problem but I don't know if you just wanted pointers or if you wanted an actual solution...
    Proving that not only archers do math since 2009. b:victory
    Current math challenge: pwi-forum.perfectworld.com/showthread.php?t=1029711&page=45
    [SIGPIC][/SIGPIC]
    "Any skills that can be used to kill you will interrupt BB when successful." -truekossy | "...Sage archers are kind of like Mac owners. They are proud of the weirdest and most unnecessary things." -Aesthor | "We ALL know Jesus doesn't play PWI. He may have suffered a lot for humanity, but he'd NEVER punish himself this way." -Abstractive | "I approve of bananas." -SashaGray
  • foodgasm
    foodgasm Posts: 4 Arc User
    edited October 2012
    Decus - Dreamweaver wrote: »
    Guess I'll take the problem Cheze didn't claim. Also, I'll assume you are allowed to use L'Hopital's rule since it doesn't say you cannot.

    As it stands, the current limit is not indeterminate unless b = 3. So, let's set b = 3. Since now it would result in the form 0/0, we can take the derivative of the top and bottom. I can keep on going to solve this problem but I don't know if you just wanted pointers or if you wanted an actual solution...

    Pointers is fine. Like I have the profs solution and method I just need to understand how or why he did it like that or if there's another way to go about doing the question. Is there another method besides L'Hopital's? Cause we havent done that yet.
  • Mitachi - Dreamweaver
    Mitachi - Dreamweaver Posts: 1,201 Arc User
    edited October 2012
    Well i got this interesting equation in my textbook, im not really good with shapes but i found this kind of easy.

    Derp
    lalalala Pokemon
    [SIGPIC]http://th06.deviantart.net/fs71/200H/f/2011/187/1/b/dragonite_by_silver_noctis-d3l67zm.jpg[/SIGPIC]
  • Decus - Dreamweaver
    Decus - Dreamweaver Posts: 5,033 Arc User
    edited October 2012
    foodgasm wrote: »
    Pointers is fine. Like I have the profs solution and method I just need to understand how or why he did it like that or if there's another way to go about doing the question. Is there another method besides L'Hopital's? Cause we havent done that yet.

    Yep, can do it without L'Hopital's rule as well, just requires a bit more finesse. Let's see if I can do this without giving too much away...

    Rationalizing the denominator first and moving some terms around should get you to a point where you have a term that looks like [ sqrt(-a*abs(x) + b) - b ] / x somewhere in the limit. That term can be equated to the limit definition of the derivative through a simple substitution. Then, it all falls into place neatly.
    Proving that not only archers do math since 2009. b:victory
    Current math challenge: pwi-forum.perfectworld.com/showthread.php?t=1029711&page=45
    [SIGPIC][/SIGPIC]
    "Any skills that can be used to kill you will interrupt BB when successful." -truekossy | "...Sage archers are kind of like Mac owners. They are proud of the weirdest and most unnecessary things." -Aesthor | "We ALL know Jesus doesn't play PWI. He may have suffered a lot for humanity, but he'd NEVER punish himself this way." -Abstractive | "I approve of bananas." -SashaGray
  • FayHumming - Dreamweaver
    FayHumming - Dreamweaver Posts: 325 Arc User
    edited October 2012
    b:tired math so bored
    the survival of the fittest

    -Thx all suport sell me SoW for 5M b:thanks tome/ring
    !!!SUPPORT OUR TROOPS!!!
  • Decus - Dreamweaver
    Decus - Dreamweaver Posts: 5,033 Arc User
    edited October 2012
    FayHumming - Dreamweaver wrote: »
    b:tired math so bored

    Don't let the door hit you on the way out. b:bye
    Proving that not only archers do math since 2009. b:victory
    Current math challenge: pwi-forum.perfectworld.com/showthread.php?t=1029711&page=45
    [SIGPIC][/SIGPIC]
    "Any skills that can be used to kill you will interrupt BB when successful." -truekossy | "...Sage archers are kind of like Mac owners. They are proud of the weirdest and most unnecessary things." -Aesthor | "We ALL know Jesus doesn't play PWI. He may have suffered a lot for humanity, but he'd NEVER punish himself this way." -Abstractive | "I approve of bananas." -SashaGray
  • Mitachi - Dreamweaver
    Mitachi - Dreamweaver Posts: 1,201 Arc User
    edited October 2012
    Decus - Dreamweaver wrote: »
    Don't let the door hit you on the way out. b:bye

    +1

    Math ftw, especially when you figure out how to do something. Its like ooooh damn that was a stupid mistake i made.
    lalalala Pokemon
    [SIGPIC]http://th06.deviantart.net/fs71/200H/f/2011/187/1/b/dragonite_by_silver_noctis-d3l67zm.jpg[/SIGPIC]
  • Labs - Dreamweaver
    Labs - Dreamweaver Posts: 11 Arc User
    edited October 2012
    Mitachi - Dreamweaver wrote: »
    +1

    Math ftw, especially when you figure out how to do something. Its like ooooh damn that was a stupid mistake i made.

    Mita Mita Mitachiiiiiiiiiiiiiiiiiiiiiiiiiiii !!! b:bye
  • Mitachi - Dreamweaver
    Mitachi - Dreamweaver Posts: 1,201 Arc User
    edited October 2012
    Labs - Dreamweaver wrote: »
    Mita Mita Mitachiiiiiiiiiiiiiiiiiiiiiiiiiiii !!! b:bye

    LABSY NABSY PANZY b:kiss
    lalalala Pokemon
    [SIGPIC]http://th06.deviantart.net/fs71/200H/f/2011/187/1/b/dragonite_by_silver_noctis-d3l67zm.jpg[/SIGPIC]
  • Labs - Dreamweaver
    Labs - Dreamweaver Posts: 11 Arc User
    edited October 2012
    Mitachi - Dreamweaver wrote: »
    LABSY NABSY PANZY b:kiss

    b:kissb:cry mish euu !!!
  • Aracnius - Dreamweaver
    Aracnius - Dreamweaver Posts: 131 Arc User
    edited October 2012
    more math!
    [SIGPIC][/SIGPIC] b:surrender
    -Waiting for the day they replace these stupid bear smilies with monkey ones
  • Decus - Dreamweaver
    Decus - Dreamweaver Posts: 5,033 Arc User
    edited October 2012
    Aracnius - Dreamweaver wrote: »
    more math!

    On it. These aren't as 'cute' as the last ones, but I rather like manipulating expressions too, so deal with it. I also made 3 appropriate for Hallowe'en :3


    1) Compute the number of degrees in the smallest possible angle x such that 8(sin x)(cos x)^5 - 8(cos x)(sin x)^5 = 1

    2) Suppose that f(x) = 1^3 + 2^3 + ... + x^3 and g(x) = 1 + 2 + ... + x. Compute the value of f(1)/g(1) + f(2)/g(2) + ... + f(1000)/g(1000)

    3) Picture yourself in the center of a circular pond 100 meters in radius, and a zombie on the pond's edge that wants to eat you, but can't swim. The zombie can walk 4 m/sec. You can swim 1 m/sec and run 7 m/sec. Can you escape the zombie? If so, describe your strategy for reaching the shore first. If not, describe the zombie's strategy for catching you!
    (Assume you and the zombie can change direction instantly without losing time. Not only can't the zombie swim, it can't go into the pond nor jump in on top of you. Show your steps, formulas, and reasoning.)
    Proving that not only archers do math since 2009. b:victory
    Current math challenge: pwi-forum.perfectworld.com/showthread.php?t=1029711&page=45
    [SIGPIC][/SIGPIC]
    "Any skills that can be used to kill you will interrupt BB when successful." -truekossy | "...Sage archers are kind of like Mac owners. They are proud of the weirdest and most unnecessary things." -Aesthor | "We ALL know Jesus doesn't play PWI. He may have suffered a lot for humanity, but he'd NEVER punish himself this way." -Abstractive | "I approve of bananas." -SashaGray
  • Sirrobert - Dreamweaver
    Sirrobert - Dreamweaver Posts: 3,395 Arc User
    edited October 2012
    Decus - Dreamweaver wrote: »
    3) Picture yourself in the center of a circular pond 100 meters in radius, and a zombie on the pond's edge that wants to eat you, but can't swim. The zombie can walk 4 m/sec. You can swim 1 m/sec and run 7 m/sec. Can you escape the zombie? If so, describe your strategy for reaching the shore first. If not, describe the zombie's strategy for catching you!
    (Assume you and the zombie can change direction instantly without losing time. Not only can't the zombie swim, it can't go into the pond nor jump in on top of you. Show your steps, formulas, and reasoning.)

    Dive down and get a good sized rock from the bottom of the lake, and throw it at the zombie.
    Repeat until zombie stops moving
    9 out of 10 voices in my head say I'm not crazy... the 10th is singing the music of tetris
  • Mooooooooo - Lost City
    Mooooooooo - Lost City Posts: 377 Arc User
    edited October 2012
    Decus - Dreamweaver wrote: »
    3) Picture yourself in the center of a circular pond 100 meters in radius, and a zombie on the pond's edge that wants to eat you, but can't swim. The zombie can walk 4 m/sec. You can swim 1 m/sec and run 7 m/sec. Can you escape the zombie? If so, describe your strategy for reaching the shore first. If not, describe the zombie's strategy for catching you!
    (Assume you and the zombie can change direction instantly without losing time. Not only can't the zombie swim, it can't go into the pond nor jump in on top of you. Show your steps, formulas, and reasoning.)

    When you are less than 25m from the center of the pool. swim in a circle until you position yourself exactly opposite of the zombie. This is possible since the circle you are swimming in is less than 1/4 of the circle the zombie must run in. Now you are 75m from the edge, and the zombie is ~314 from the edge. You just swim to the edge in a straight line. and then you take a **** for 3 seconds, then you jump back in the water and have fun playing with the zombie like this.
    youtube channel: youtube.com/user/chezedude
  • Mooooooooo - Lost City
    Mooooooooo - Lost City Posts: 377 Arc User
    edited October 2012
    decus - Dreamweaver wrote: »
    1) Compute The Number Of Degrees In The Smallest Possible Angle X Such That 8(sin X)(cos X)^5 - 8(cos X)(sin X)^5 = 1

    7.5
    .
    youtube channel: youtube.com/user/chezedude
  • Mooooooooo - Lost City
    Mooooooooo - Lost City Posts: 377 Arc User
    edited October 2012
    decus - Dreamweaver wrote: »

    2) Suppose That F(x) = 1^3 + 2^3 + ... + X^3 And G(x) = 1 + 2 + ... + X. Compute The Value Of F(1)/g(1) + F(2)/g(2) + ... + F(1000)/g(1000)

    167167000
    youtube channel: youtube.com/user/chezedude
  • truekossy
    truekossy Posts: 7,021 Arc User
    edited October 2012
    Sirrobert - Dreamweaver wrote: »
    Dive down and get a good sized rock from the bottom of the lake, and throw it at the zombie.
    Repeat until zombie stops moving

    This is the most practical answer. b:chuckle
  • Sirrobert - Dreamweaver
    Sirrobert - Dreamweaver Posts: 3,395 Arc User
    edited October 2012
    truekossy wrote: »
    This is the most practical answer. b:chuckle

    Ikr
    He can't get in the water, so you can get up to 1 meter away from him without any danger (easy aim). And you can asume a lake is filled with rocks b:victory
    9 out of 10 voices in my head say I'm not crazy... the 10th is singing the music of tetris
  • truekossy
    truekossy Posts: 7,021 Arc User
    edited October 2012
    Sirrobert - Dreamweaver wrote: »
    Ikr
    He can't get in the water, so you can get up to 1 meter away from him without any danger (easy aim). And you can asume a lake is filled with rocks b:victory
    And if that fails, you can try to force it into the water where it'd be screwed while you swim out. Either way zombie can't win.
  • Decus - Dreamweaver
    Decus - Dreamweaver Posts: 5,033 Arc User
    edited October 2012
    I'm starting to think this thread is only for the benefit of cheze.
    Proving that not only archers do math since 2009. b:victory
    Current math challenge: pwi-forum.perfectworld.com/showthread.php?t=1029711&page=45
    [SIGPIC][/SIGPIC]
    "Any skills that can be used to kill you will interrupt BB when successful." -truekossy | "...Sage archers are kind of like Mac owners. They are proud of the weirdest and most unnecessary things." -Aesthor | "We ALL know Jesus doesn't play PWI. He may have suffered a lot for humanity, but he'd NEVER punish himself this way." -Abstractive | "I approve of bananas." -SashaGray
  • truekossy
    truekossy Posts: 7,021 Arc User
    edited October 2012
    Decus - Dreamweaver wrote: »
    I'm starting to think this thread is only for the benefit of cheze.

    I like it! Even if I never actually answer in favor of giving vague hints if Cheze hasn't already answered a question that amused me.
  • Sirrobert - Dreamweaver
    Sirrobert - Dreamweaver Posts: 3,395 Arc User
    edited October 2012
    You should make cheze come refine our gear like he does in Lost City, as thanks for this thread
    9 out of 10 voices in my head say I'm not crazy... the 10th is singing the music of tetris
  • truekossy
    truekossy Posts: 7,021 Arc User
    edited October 2012
    Or you could do what he does to make much moolah.
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