24小时热门版块排行榜    

查看: 1343  |  回复: 5
当前只显示满足指定条件的回帖,点击这里查看本话题的所有回帖

sdcdzt

新虫 (初入文坛)

[求助] 求解二阶非线性常微分方程!!!解决之后另有重谢!!! 已有2人参与

dz(2)和dz(4)是z1,z2的二阶导,z(2),z(4)是z1,z2的一阶导。方程里最高阶项是耦合的。



dz(2) + (8165768846995289*z(1))/43980465111040 + 260*z(2) + (729274196212461*z(1)^2*z(3)^2)/657666867200 - (810461751221981*z(1)^2*z(3)^3)/770703360000 + (1056424101821091*z(1)^3*z(3)^2)/2055208960000 + (8722212816045573*dz(4)*z(3))/3777893186295716170956800 - (6306482750015563*z(1)*z(3))/858993459200 + (7086797913037029*z(3)*z(4))/11805916207174113034240 - (756465654738930894864411090880955416576*v^2*((5583899589019513*z(1)^2)/28823037615171174400 - (1535799397223231*z(1)*z(3))/2882303761517117440 + (1705094118577331*z(3)^2)/1801439850948198400))/1726659758420692373277280879638240234375 + (6240407844064763*dz(4)*z(3)^2)/483570327845851669882470400 - (3584792003555446609710148086013952*v^2*((5616914817747799*z(1))/219902325555200 - (4981953625221941*z(3))/219902325555200))/1726659758420692373277280879638240234375 + (4800904038295969*z(1)*z(3)^2)/140928614400 - (4926513293399861*z(1)^2*z(3))/493250150400 - (7448269298026523*z(1)*z(3)^3)/3946001203200 - (1754174731218613*z(1)^3*z(3))/8418135900160 + (1349947142680613*z(1)*z(3)^4)/1233125376000 - (4778439099191479*z(1)^4*z(3))/49325015040000 + (253516568665131*z(3)^2*z(4))/75557863725914323419136 - (756465654738930894864411090880955416576*v^2*((5584448069578993*z(1)^2)/115292150460684697600 - (6186436149201411*z(1)*z(3))/28823037615171174400 + (5375473397785631*z(3)^2)/11529215046068469760))/1726659758420692373277280879638240234375 + (41486480788177196822439296062044766208*v^2)/115110650561379491551818725309216015625 + (1375585107332589*z(1)^2)/2748779069440 + (5931535843587817*z(1)^3)/6313601925120 + (3741979822281889*z(1)^4)/101017630801920 + (4577882713395029*z(3)^2)/214748364800 + (6818002503693121*z(1)^5)/526133493760000 - (262863617127891*z(3)^3)/46976204800 + (3438474728478809*z(3)^4)/1973000601600 - (811723297025401*z(3)^5)/112742891520000=0
dz(4) + (297872865246189*z(1))/5629499534213120 + 260*z(4) - (563948109211209*z(1)^2*z(3)^2)/858993459200 + (1509940229868547*z(1)^2*z(3)^3)/2055208960000 - (899018850540299*z(1)^3*z(3)^2)/3758096384000 + (3584792003555446609710148086013952*v^2*((311265982272027*z(1))/13743895347200 - (5439582840008959*z(3))/27487790694400))/1726659758420692373277280879638240234375 - (756465654738930894864411090880955416576*v^2*((7021818610175179*z(1)*z(3))/7205759403792793600 - (5967775428393763*z(1)^2)/57646075230342348800 + (681586795427753*z(3)^2)/1441151880758558720))/1726659758420692373277280879638240234375 + (3298744320994199*dz(4)*z(3))/236118324143482260684800 + (4647990245028827*z(1)*z(3))/214748364800 + (5360459521615573*z(3)*z(4))/1475739525896764129280 + (4720249406991477*dz(4)*z(3)^2)/60446290980731458735308800 - (2922476536051257*z(1)*z(3)^2)/164416716800 + (774060836814941*z(1)^2*z(3))/35232153600 + (19783176809747*z(1)*z(3)^3)/11744051200 + (1753869418212413*z(1)^3*z(3))/5261334937600 - (6448419081252833*z(1)*z(3)^4)/31568009625600 + (2956279016688527*z(1)^4*z(3))/32883343360000 + (767040528636115*z(3)^2*z(4))/37778931862957161709568 + (31759674132034291766388478409227370496*v^2)/191851084268965819253031208848693359375 - (4870310409024751*z(1)^2)/43980465111040 - (4158104683784381*z(1)^3)/6313601925120 - (7911407438985527*z(1)^4)/1010176308019200 + (4164490152882159*z(3)^2)/274877906944 - (2403471885628813*z(1)^5)/1578400481280000 + (1454845076733109*z(3)^3)/24662507520 + (890364628444807*z(3)^4)/1683627180032 + (1162785006804349*z(3)^5)/2466250752000 - (756465654738930894864411090880955416576*v^2*((1612342847780083*z(1)*z(3))/115292150460684697600 + (3202078393359277*z(1)^2)/57646075230342348800 + (3408158844499937*z(3)^2)/28823037615171174400))/1726659758420692373277280879638240234375=0
回复此楼

» 猜你喜欢

» 本主题相关价值贴推荐,对您同样有帮助:

已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

月只蓝

主管区长 (职业作家)

【答案】应助回帖

引用回帖:
2楼: Originally posted by 月只蓝 at 2014-04-15 21:35:43
方程很复杂,不过解二阶非线性方程的方法还是很成熟的:
比如  y''=f
令  y1=y, y2=y'
原方程化为常微分方程组:
y1'=y2
y2'=f

加上初值或者边值条件,MATLAB的ode45或者ode15s ode23s即可解。

补充一下
MATLAB的ode45或者ode15s ode23s适合于初值问题哈
MATLAB、MS小问题、普通问题请发帖求助!时间精力有限,恕不接受无偿私信求助。
3楼2014-04-15 21:39:23
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
查看全部 6 个回答

月只蓝

主管区长 (职业作家)

【答案】应助回帖

感谢参与,应助指数 +1
方程很复杂,不过解二阶非线性方程的方法还是很成熟的:
比如  y''=f
令  y1=y, y2=y'
原方程化为常微分方程组:
y1'=y2
y2'=f

加上初值或者边值条件,MATLAB的ode45或者ode15s ode23s即可解。
MATLAB、MS小问题、普通问题请发帖求助!时间精力有限,恕不接受无偿私信求助。
2楼2014-04-15 21:35:43
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

sdcdzt

新虫 (初入文坛)

引用回帖:
3楼: Originally posted by 月只蓝 at 2014-04-15 21:39:23
补充一下
MATLAB的ode45或者ode15s ode23s适合于初值问题哈...

这些都用过。都不适用。因为我这个方程里连最高阶项都是二次的。ode45根本解不了。
4楼2014-04-17 19:22:47
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

sdcdzt

新虫 (初入文坛)

引用回帖:
3楼: Originally posted by 月只蓝 at 2014-04-15 21:39:23
补充一下
MATLAB的ode45或者ode15s ode23s适合于初值问题哈...

说错了,最高阶项是非线性的
5楼2014-04-17 19:24:28
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
信息提示
请填处理意见