I understand that you would like to obtain the bode plot of a dynamic system in MATLAB.
Although I did not understand the terminology you have used in the equation you had mentioned in the question, I would like to point out a few things in general context.
First of all, assuming 'x' as input and 'y' as the output of the dynamic system, the plot(x, abs(y(x))) does not give you the Bode plot. Note that Bode plot is in logarithmic scale and it requires the transfer function corresponding to the linear system.
In order to use 'bode()' in MATLAB, you need to first get the state space or transfer function representaion of your linear (or linearised) system. This information is given as input to the 'bode()' function. Once you have this, use the following documentation on bode() function to know more about its use: https://in.mathworks.com/help/control/ref/bode.html
I hope you will find this post useful.
