# Plotting a Sequence over a Given Interval

2 views (last 30 days)
Connor Wright on 9 Jan 2021
Answered: Star Strider on 9 Jan 2021
I am trying to plot the follwing sequence,
𝑥(𝑛) = 𝑛[𝑢(𝑛) − 𝑢(𝑛 − 10)]+ 10𝑒 −0.(𝑛−10) [𝑢(𝑛 −10) − 𝑢(𝑛 − 20)]
Over this interval
0 ≤ 𝑛 ≤ 20
I already have some code from a previous attempt at this type of problem which is as follows,
% USMPL Function %
function delta = usmpl(n)
if n == 1
delta = 1
else
delta = 0
end
% Main Code %
n = -10:10
x = zeros(length(n)
for k = 1:length(n)
x(k) = 2*usmpl(n(k)+ 1) - usmpl(n(k)-6);
end
stem(n,x)
The problem I am having is working out what to put where in this code to make it work for this problem.
Thanks.
Connor Wright on 9 Jan 2021
So would it be feesible to just modify my USMPL code and make u the focus instead of delta?

Star Strider on 9 Jan 2021
I have no idea.
I would just do something like this, and hope for the best with respect to whatever that exp() call is supposed to do:
u = @(t) t>=1;
x = @(n) n.*(u(n)-u(n-10) + 10*exp(-0*(n-10)) .* (u(n-10)-u(n-20)));
n = linspace(0, 20, 1000);
figure
plot(n, x(n))
grid
Make appropriate changes when you resolve the problem with the exponential term.

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