Help with nested for loop, for a matlab hw problem

So i've been working on this problem for a while and not really sure what i'm doing, can someone point me in the right direction

this is my code so far

clc
clear all
t=linspace(0,10,500);

omaga_d_1=.5;

omaga_d_2=1.1;
omaga_d_3=1.5;
sigma_d=3.5;
sigma_d_1=5;
for i=1:t;
    c=5*exp.^(-omaga_d_1*t).*cos(sigma_d*t);
end
plot(t,c)

Answer 1

[KSSV]

clc; clear all ;
t=linspace(0,10,500);
omaga_d=[.5 1.1 1.5 3.5]; 
sigma_d=5; 
c = zeros(length(omaga_d),length(t)) ;
for i = 1:length(omaga_d)
    c(i,:)=5*exp(-omaga_d(i)*t).*cos(sigma_d*t); 
end
plot(t,c)

Answer 2

[Adam]

sigma_d = [0.5 1.1 1.5];
omega_d = [3.5 5.0];

Put those into arrays to start with (you got them the wrong way round too so far as I can see). Those are then the two arrays you are expected to loop over in your nested for loops.

I'm not going to do the whole question for you because it is homework but that is a step in the right direction.