MATLAB: The plot doesn’t show the line

plot

I'm very new with this program. Here is my code. Am I missing something? Could someone fix it and explain to me, thank you.
c = 3*10^8;
f0 = 10^9;
d0=10^3;
for i = 1:100
f1 = 1/(10*i/(c+10));
fd = f1-f0;
plot(i,fd)
hold on
end

Best Answer

If you must use a loop, you need to subscript ‘f1’: 
f1(i) = 1/(10*i/(c+10));
However a loop is not necessary. Using element-wise operations, this works: 
c = 3*10^8;
f0 = 10^9;
d0=10^3;
i = 1:100;
f1 = 1./(10*i/(c+10));
fd = f1-f0;
plot(i,fd)
See Array vs. Matrix Operations for details.
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