Question on Initial value problem - error correction
显示 更早的评论
Question
I create a script
function f = exercise711 (t, x)
f = t * x.^2;
end
And on the command window, I wrote
>> [t1, x1] = ode45(@exercise711, [0 1], 1);
>> plot(t1, x1)
>> hold on
>> [t2, x2] = ode45(@exercise711, [0 2], 1);
Warning: Failure at t=1.414192e+00. Unable to meet integration tolerances
without reducing the step size below the smallest value allowed
(3.552714e-15) at time t.
In ode45 (line 308)
>> plot(t2, x2)
here, for the interval [0 2], I get an error and the graph is wrong. Why? How can I correct it? Please help me to do this question in a correct way.
Thanks a lot.
采纳的回答
Ameer Hamza
2020-4-24
编辑：Ameer Hamza
2020-4-24
0 个投票
The result is correct, and it was the purpose of the exercise to show that the solution of an ODE can diverge to infinity. If you use symbolic toolbox to solve this equation, you can see that the analytical solution of this ODE is
and at 
, there is a singularity and the output become infinity. You can see in warning message that the issue also occurs at 1.414... In the interval [0,1] there is no singularity and MATLAB does not give any warning.
, there is a singularity and the output become infinity. You can see in warning message that the issue also occurs at 1.414... In the interval [0,1] there is no singularity and MATLAB does not give any warning.6 个评论
Zeynep Toprak
2020-4-24
Ameer Hamza
2020-4-24
I am glad to be of help.
Zeynep Toprak
2020-5-7
Zeynep Toprak
2020-5-7
Ameer Hamza
2020-5-7
That question requires a bit of thinking. I will answer it if I get some ideas.
Zeynep Toprak
2020-5-7
thanks a lot. In fact, very similart question is here
But, I am writing D1 matrix in wrong way. If I can correct it, this solution is valid, i think. Again, thank you for your consideration, and helping.
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Mathematics 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
