Hello Berkin,
As per my understanding, you want to group all the items in your equation as quadratic or squared terms.
I recommend you leverage the symbolic variables and the symbolic algebra capabilities of MATLAB for this purpose. You can first create ‘x1’, ‘x2’,’a’ and ‘b’ as symbolic scalar variables of type ‘sym’. Then, you can define your equation in a separate variable after which you can use the ‘collect’ function to group the quadratic terms (x1^2 and x2^2) and squared terms. Refer to the following code snippet for an overview of the method.
%Creating the symbolic variables
syms x1 x2 a b c
%Defining the equation
equation = (-a-b)*x1^2 + 0.2*b*x1*x2 - 0.2*c*x2^2;
% Grouping the quadratic terms (This grouped_equation variable contains the
% new equation)
grouped_equation = collect(equation, [x1^2, x2^2]);
By using symbolic variables, you can easily update your equation in the future and MATLAB will automatically group the quadratic terms for you.
Refer to the following documentation to understand more about ‘syms’ and ‘collect’ functions.
Hope this helps!
