how to make for loop for sine waves and composite sine wave?

X= [0.3, 0.5, 0.7, 2.5] ;
Y= [2, 4, 6, 8] ;
% Z= sum(Y*sin(X*t) --- would like each component overplotted                
% SUM- copy-paste works - z= z1+ z2+ z3+ z4 (4 z's- how do we auto?)
t= linspace(0, 2*pi, 100) ; 
z1= Y(1)*sin(X(1)*t) ;
z2= Y(2)*sin(X(2)*t) ;
z3= Y(3)*sin(X(3)*t) ;
z4= Y(4)*sin(X(3)*t) ;
figure
hold on
plot(t, z1)
plot(t, z2)
%etc.
hold off

I tried doing something like

t= linspace(0, 2*pi, 100) ;  % need to make a t vector?
for i= 1: length(X) ;
    for j= 1: length(Y) ;
        Zn(ij)= Y*sin(X*t) ;
        end
end
plot(t, Zn)

but it doesn't work. I understand why it is wrong but I don't really know how to fix it.

Answer 1

[Walter Roberson]

X = [0.3, 0.5, 0.7, 2.5] ;
Y = [2, 4, 6, 8] ;
t = linspace(0, 2*pi, 100) ; 
Z = sum(Y(:).* sin(X(:).* t));

plot(t,Z)

[BGN]

thank you!