# Find the meaning of each line of code

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surendra agrawal on 21 Jun 2021
Edited: Image Analyst on 24 Jun 2021
clearvars
clc
syms y(t) s Y Dy(t)
C = input('Enter the coeff. of D2y, Dy and y as an array: ');
F = input('Enter the non-homogeneous part f(t): ');
IC = input('Enter the initial conditions [y0 Dy0]: ');
DEq = C(1)*diff(y,2)+C(2)*diff(y,1)+C(3)*y -F;
LDEq = laplace(DEq);
LDEq1 = subs(LDEq,{laplace(y(t),t,s),y(0),subs(diff(y(t), t), t, 0)},{Y, IC(1),IC(2)});
Ys = solve(LDEq1,Y);
y = collect(simplify(ilaplace(Ys)));
disp('The solution of the given DE is: ');
disp(char(y))
fplot(y)
title('Plot of the Solution')
##### 2 CommentsShowHide 1 older comment
Walter Roberson on 21 Jun 2021
I have a personal policy not to give explanation of the code in situations such as this.
When someone asks to have ever line explained, but does not give any specific questions or discuss the concepts involved, then we as volunteers have to assume that the person doing the asking might not have any computing experience at all, and might not have even know things like "positional notation"... let alone have any experience with the topic (such as differential equations.)

Divija Aleti on 24 Jun 2021
Hi Surendra,
As KSSV mentioned, do read the documentation of each function used in the code. It will be self-explanatory.
Hope this helps!
Regards,
Divija

Image Analyst on 24 Jun 2021
Edited: Image Analyst on 24 Jun 2021
Since you didn't write it yourself, I'd contact the author and ask them why they wrote such poor code with no comments and variable names that are not descriptive at all. It's an alphabet soup mess of a program. Ask the author to write like a professional programmer and correct it so that it's virtually self-documenting. It's their fault, not yours, and they should fix it. I train our programmers not to write bad code like that.
See Loren's blog