write a function to represent the system in the form of a differential equation, and solve it with each set of values using the ode45 function in matlab

To represent the system in the form of a differential equation, we need to first have a clear understanding of the system. Once we have that, we can write the differential equation(s) based on the system.

To solve the differential equation(s) using ode45 function in Matlab, you should follow the following steps:

  1. Define the differential equation(s) for the given system as an anonymous function. Let's say you have a first-order differential equation: dy/dt = f(t, y) where t is the time and y is the dependent variable.

    main.m
    f = @(t, y) t-y; % Example differential equation
    
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  2. Set the time span for the solution, i.e. the start and end times.

    main.m
    tspan = [0 10]; % Example time span from 0 to 10 seconds
    
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  3. Define the initial condition for the dependent variable, which is the value of y at the start time tspan(1).

    main.m
    y0 = 1; % Example initial condition
    
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  4. Solve the differential equation(s) using ode45 function. ode45 uses an adaptive timestep to solve the differential equation(s) numerically.

    main.m
    [t, y] = ode45(f, tspan, y0);
    
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    Here, t is a vector of time values and y is a vector of corresponding solutions for the dependent variable.

    Note: If the differential equation(s) involve multiple dependent variables, then we have to define all the variables in the anonymous function and initial condition, and provide multiple initial conditions in a row vector.

    Also, there are other options in ode45 that can be used to control the relative and absolute error tolerances, maximum step size, and more. You can read more about them in the Matlab documentation.

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