Help writting a simple code!

I'm trying to make a Simulink model consisting of a clock (as a source) and a MATLAB function that calculates the following:

Y=exp(t) * sigma(n=1:inf)[n * exp(n*t)]

Can anybody help me write the code?

Answer 1

[Paulo Silva]

MATLAB Fcn

exp(u)*sum([1:10].* exp([1:10].*u)) %not infinite sum but close enough

Answer 2

[C.J. Harris]

You won't be able to write an infinite series directly. You will either have to use an approximation, or only calculate the sum for the first 'n' elements.

Answer 3

[Walter Roberson]

If and only if t is less than 0,

Y = exp(2*t)/(exp(t)-1)^2

That is, sum(n*exp(n*t), n = 1 .. infinity) is exp(t)/(exp(t)-1)^2

If t is 0 or greater, the sum is infinite, as you are adding together numbers that increase infinitely.

Answer 4

[Hossein sadri]

tnx for the answers....and what should i do when i want to do same thing with sigma(n^2*exp(u))?im encountering the error matrix must be squer using [1:10]^2....

[Paulo Silva]

[1:10].^2

[Walter Roberson]

n.^2 instead of n^2

But n^2*exp(u) has the same problem I described above of having an infinite value unless u is negative.

Answer 5

[amey]

n=1:1:100; y=exp(0.4)*(n.*exp(0.4*n)); tot=0; for i=1:100; tot=tot+y(i); end disp(tot);

[amey]

u = 0.4 ; % assumed

n=1:1:100; % only first 100 terms taken

[Paulo Silva]

is there another question for us?