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b*****n
发帖数: 7 | 2 Thank you so much for your answer!
But do you think the left side can be integrated? I cannot find the original
function, whose derivative is in such a form. |
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w**a
发帖数: 1024 | 3 i don't exactly know the answer.but
i guess so, also depends on your initial y(0).
just imagine you have a pendulum, given position, it must get some time to '
swing' back and forth, under permissible condition. |
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w**a
发帖数: 1024 | 4 感觉像一个动力系统得东东
把y看作位置，x作为时间。
y' 就是速度。问题变成给定速度场，求位置。
有些情况方程无实数解吧，如 2siny+cos(y) > -1.
请把问题在具体一点。定义于，值域，实数解还是复数解等等。。。。 |
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t**********r
发帖数: 256 | 5 用不着那么复杂，mathematica,maple各试一遍，如果没有解析解，
不是专业搞ODE李群分析的就可以放弃了。 |
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w**a
发帖数: 1024 | 7 你还可以对方程 求导 w.r.t. x
如果还不行， 你可以参考这本书，刚开始得几页，有类似问题。
Chaos and Integrability in Nonlinear Dynamics: An Introduction
by Michael Tabor |
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b*****n
发帖数: 7 | 8 Is it possible to calculate t given some y(t)=c where c is a real number?
. |
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w**a
发帖数: 1024 | 9 take d/dx both sides
you got
(1) y'=0. in this case there are many solutions. e.g., y=3.141592...
(2) 2y"=sin(y) - 2 cos(y). This is similar to the solution for Swinging
Pendulum.
you can see this by write all the sin and cos into one single sin() or cos().
the typical eq. governing swinging pendulum is
y" + g/L sin(y) = 0.
The perid is T= (5/4)^0.25.
as far as i know , in 2nd case, which is also the interesting one,
there is no analytical solution. if you want to study its local behavior. use
e |
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V******G
发帖数: 285 | 11 【 以下文字转载自 NextGeneration 讨论区 】
发信人: VampireG (GiGi), 信区: NextGeneration
标 题: 转4moms MamaRoo
发信站: BBS 未名空间站 (Sat Oct 13 15:33:31 2012, 美东)
转一个自己超喜欢的摇篮，状态很好，平时用的不多（家里老人爱抱着孩子），去年圣
诞为老二准备的，三月份才开始使用。自带ipod, iphone, ipad接口，可以播放音乐。
晃动的幅度强度都可以调节。废话不多说了，感兴趣的MM可以看下youtube上的介绍。http://www.youtube.com/watch?v=ftzlGEEu9Oc
原价234+税，现转：$95, 另有3款推车转（quinny buzz, maclaren volo, maclaren
quest)，Maxi-cosi infant carseat (可与推车配合使用，附带carseat adapter),一
个闲置combi infant carseat 送感兴趣的站内。
location: 巴尔的摩附近 ， zip :21001 |
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c*********d
发帖数: 9770 | 12 张春桥：论对资产阶级的全面专政（On Exercising All-Round Dictatorship Over
the Bourgeoisie）
无产阶级专政问题，是长期以来马克思主义同修正主义斗争的焦点。列宁说“只有承认
阶级斗争、同时也承认无产阶级专政的人，才是马克思主义者。”
THE question of the dictatorship of the proletariat has long been the focus
of the struggle between Marxism and revisionism. Lenin said, “Only he is a
Marxist who extends the recognition of the class struggle to the recognition
of the dictatorship of the proletariat.” And it is precisely to enable us
to go by Marxism and not revisionism in both theory an... 阅读全帖 |
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K********r
发帖数: 616 | 13 cosi的沙拉比麦当劳的好吃多了，你要不要去试试？ |
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C******g
发帖数: 2930 | 14 不过据说画面比较落后点和现阶段的别的游戏比的话。
Namco has spilled the beans on Tekken 6’s extensive online component ahead
of the hotly anticipated beat ‘em up’s release on PlayStation 3 and Xbox
360 later this month.
As well as taking part in both competitive and cooperative online game modes
, PS3 owners can look forward to soaking up some exclusive PlayStation Home
content via the Tekken 6 lounge, where you’ll be able to host various
matches and bag extra costumes and furniture for your cosy personal space.
The ful |
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g*******7
发帖数: 236 | 16 想买个convertible car seat 。宝宝是个子较高和体重比较重的那种。 maxi cosi和
Britaz 哪个好些。或者别的好用的牌子。
谢谢！ |
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l****r
发帖数: 21884 | 17 我家买了两个britax marathon, 用着挺满意。他家算性价比高的了。我俩娃也算比较
高的
Maxi cosi 没研究过
★ 发自iPhone App: ChineseWeb 8.6 |
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w*******y
发帖数: 60932 | 18 For those who want to find something besides the OSU Buckeyes to enjoy in
central Ohio, Experience Columbus has teamed up with lots of local
attractions & restaurants to offer 25-50% off this weekend. PDF included
below, and a small sample of the deals include:
Attractions:
50% off Segway tour
50% off COSI
50% off Columbus Zoo (be sure to see the underwater polar bears:
http://www.youtube.com/watch?v=ehd_yxdhBeQ
)
50% off Shadowbox Tickets
50% of select Professional Bull Riders tickets
Restaura... 阅读全帖 |
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w*******y
发帖数: 60932 | 19 $15 off of $150 at J&R:
http://www.jr.com/
Use coupon code PRESDAY at checkout.
One coupon per person. Not valid with other offers, coupons & promotions,
gift cards, PC Netbooks, Bose, Miele, all Video Game consoles, and select
products from Nikon, Olympus, Sony, Samsung, Sennheiser, Gibson, Fender,
Yamaha, Roland, Tamron lenses, Casio, Soul by Ludacris, phil&teds, Mountain
Buggy, OXO, Quinny, and Maxi Cosi, or J&R Express at Macy's Herald Square, N
.Y.
Excludes non regular priced and Sale items... 阅读全帖 |
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J********e
发帖数: 341 | 20 我看图不行，都是看着妖股涨流口水，不敢趟浑水。
next?
v=351&f=geo_usa,sh_avgvol_o100,sh_price_1to20&t=ALEX,AOB,ARDNA,BAMM,BEAV,B
TH,CBAK,CBOU,CBRL,CCH,CCK,CLU,COKE,COSI,CPWM,CRC,CRVP,DEER,DF,FARM,FLL,GAI
,GLT,GMCR,HANS,JAH,JJA,JJS,JO,JVA,KFT,KKD,KO,MCD,MIDD,MSN,NC,NPK,PEET,PNRA
,SBUX,SJM,SLE,SQM,SWY,TA,THI,THS,USBI,WFMI,WILC&o=-change |
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e***e
发帖数: 3872 | 21 泥们飘扬的都是剧本的功夫，张当然理解剧本，只是他的表达方式
没有把质朴的纯真突出出来。在偶看来，如果用质朴而不是渲染来表
达那种纯真效果会好得多，对其中的艰难，比如她送饭，等人，追车
等等，以白描叙事的手法就比他过多的摄影涂抹强调好。寓于平凡事
情中的伟大，更应该用叙述而不是夸张来展现。一个类似的例子是偶
第一次听到Horowitz弹肖邦的波兰舞曲，辉煌的高潮是通过坚定朴实
的力量达到的，还有一次听到钢琴的图画展览会，在基辅大门的一段，
那种崇高而感人的力量也是通过朴素得以突出——这常常被热爱炫技
的人因放纵自己而丧失。
在这一点上，张的处理从某种角度上可以与Life is Beautiful中的
手法作些比较。但我们常忽视的一点是，正如不少人误解Life一片中
表面轻松气氛的意图，意大利喜歌剧的手法很难‘搬’到别的文化—
—哪怕离开欧洲大陆的英伦中去。如果我们希望了解他们这样的传统
和在这种方式下表达的含义，正象我们真正了解莫扎特的‘Cosi fan
tutte’或费加罗不是一场简单闹剧一样，需要对这种手法表现的独特
性和局限性有一定的认识。 |
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e***e
发帖数: 3872 | 22 Cavalli: Delizie contente
Delizie contente, che l'alma beate Cheerful pleasures, delighting my heart
fermate, fermate. come to an end.
Su questo mio core - deh piu` non Please do not shower the joys of love
stillate
le gioie d'amore. on my heart any more.
Delizie mie care - fermatevi qui: Dear pleasures, come to an end now.
non so piu` bramare - mi basta cosi`. I ask no more, this is enough.
In grembo agli amori, fra dolci c |
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c******a
发帖数: 168 | 24 Cosi没有现场看过。魔笛是在维也纳花两块五站下来的，还去晚了（本来去得不晚，可
又饿了跑出去吃了根Bratwuerst，回来发现人家都用围巾大衣把好位置占了，结果被挤
在最偏的一个角落，有一半场子看不见。（要狠狠地抱怨这些非民主时代盖的歌剧院，
难道没钱的人连全场都都不能看么？）印象深的还是舞台设计，完全是抽象的。
Don Carlos是在Unter den Linden上看的了，还是跟干妈一块看的。那会儿她刚从维也
纳看完无名氏（对我是无名氏）指挥的荷兰人和小泽指挥的Rosenkavalier下来，仍然
很受威尔弟的震撼。这次的production是现代得出了奇，我们俩都有点接受不了：到第
三幕的时候，处死新教徒的那个场景竟然把五个裸体大男人倒挂着吊起来升上去！我俩
坐在头几排，觉得有点呕。即便如此，音乐的戏剧性还是扣人心魄。当然，演员也非常
好，毕竟是在柏林。 |
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