How to set several initial conditions when solving an ODE?

Question

Sergio Manzetti 2017-12-29

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/374898-how-to-set-several-initial-conditions-when-solving-an-ode

评论： Sergio Manzetti 2017-12-29

Hi, I have the following ODE:

if true
  % code
end
syms a h Y(x) g x B E
eqn = (h)*diff(Y,x, 2) + (g)*diff(Y,x) + (g^2 - E)*Y == 0;
cond = Y(0) == 1;
cond = (diff(Y)(0) == 0;
Y(x) = dsolve(eqn, cond)

and would like to add Y'(0)= 0 as initial condition, however cond = (diff(Y)(0) == 0; does not work. How can I combine two conditions here?

Thanks!

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

KSSV 2017-12-29

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/374898-how-to-set-several-initial-conditions-when-solving-an-ode#answer_298057

在 MATLAB Online 中打开

Check this demo from the documentation:

syms y(t) a b
eqn = diff(y,t,2) == a^2*y;
Dy = diff(y,t);
cond = [y(0)==b, Dy(0)==1];
ySol(t) = dsolve(eqn,cond)

Read more here: https://in.mathworks.com/help/symbolic/dsolve.html

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Sergio Manzetti 2017-12-29

Hi KSSV, I did this and it worked, however I am puzzled given that I still get a constant "C11" in the answer, when two conditions are given. Is this a typical example where further conditions are required to get "rid of" C11?

请先登录，再进行评论。