y = y + ( a(f)*cos(omega*f*t)+b(f)*sin(omega*f*t) ); in matlab

To write the equation in MATLAB, you need to define the variables y, a, b, omega, f, and t. Here's an example code snippet showing how you can do that:

main.m
% define variables
y = 0;
a = [1, 2, 3];
b = [4, 5, 6];
omega = 10;
f = [1, 2, 3];
t = 0.1;

% evaluate equation
for i = 1:length(f)
    y = y + (a(i)*cos(omega*f(i)*t) + b(i)*sin(omega*f(i)*t));
end
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In this example, y is initialized as zero and a and b are defined as row vectors with 3 elements. omega, f, and t are defined as scalar values.

The equation is then evaluated using a for loop, where each term in the summation is calculated for each value of f and added to y. Note that the indexing variable i is used to access the correct values of a, b, and f in each iteration.