Solve the ODE using ODE45 and plot the response for the initial conditions

Question

Kashmira Vinay 2022-10-22

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1832923-solve-the-ode-using-ode45-and-plot-the-response-for-the-initial-conditions

回答： Jan 2022-10-23

funtion xdot = ode45(x, t);
xdot = x^4 - 7*x^2 + 6*x;
%Plotting Data
%x(0) = -3.5
subplot(311)
t = (0: 0.01 : 0.5);
x = ('ode45'; -3.5; t);
plot (t,x)
%x(0) = -0.2
subplot(312)
t = (0: 0.01 : 0.5);
x = ('ode45'; -0.2; t);
plot (t,x)
%x(0) = 1.1
subplot(313)
t = (0: 0.01 : 0.5);
x = ('ode45'; 1.1; t);
plot (t,x)
%x(0) = 2.5
subplot(314)
t = (0: 0.01 : 0.5);
x = ('ode45'; 2.5; t);
plot (t,x)
endfunction

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Star Strider 2022-10-22

Your ‘ode45’ function is going to overshadow the ode45 function you are going to need to solve whatever it is you want to do.

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Answer 1

Jan 2022-10-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1832923-solve-the-ode-using-ode45-and-plot-the-response-for-the-initial-conditions#answer_1081733

在 MATLAB Online 中打开

If you call a function "ode45", it depends on where its folder is located in Matlab's path, if it is used or the original ODE45 function of Matlab. This is called "shadowing". Avoid to use names of built-in Matlab functions for your own variables and functions, because this causes many troubles.

subplot(311)

This notation is deprecated since Matlab 5.0 (1996). Use subplot(3,1,1) or the modern tiledlayout (since R2021a).

This line is not meaningful:

x = ('ode45'; -3.5; t);

Remember, that this is a Matlab forum. "endfunction" is not Matlab, but might be Octave.

Please take the time to ask a specific question.