2楼: Originally posted by ccyzrb at 2012-07-31 16:22:45
你确定你写的是对的！

3楼: Originally posted by tianya_0818 at 2012-07-31 20:04:45
式子没有问题，这位大侠觉得在运行过程中出现了什么问题吗？...

4楼: Originally posted by dingd at 2012-08-01 10:02:16
一楼的好像不太对，Dx，D2x是什么啊？

constant k1=97.2941,k2=0.0223,h1=1.9633e-3;
ConstStr h2=h1-x*tan(pi/18);
variable t=[-2,2], x=-5.5, x'=0.5;
Plot x;
ODEFunction x''=(x'-k1*h2^2*x''/(h1+h2)/k2)^2;

7楼: Originally posted by dingd at 2012-08-02 15:10:16
应该是二阶隐式常微分问题了，下面代码供参考：

constant k1=97.2941,k2=0.0223,h1=1.9633e-3;
ConstStr h2=h1-x*tan(pi/18);
variable t=, x=-5.5, x'=0.5;
Plot x;
ODEFunction x''=(x'-k1*h2^2*x''/(h1+h ...

7楼: Originally posted by dingd at 2012-08-02 15:10:16
应该是二阶隐式常微分问题了，下面代码供参考：

constant k1=97.2941,k2=0.0223,h1=1.9633e-3;
ConstStr h2=h1-x*tan(pi/18);
variable t=, x=-5.5, x'=0.5;
Plot x;
ODEFunction x''=(x'-k1*h2^2*x''/(h1+h ...