Hello, I am trying to plot the fourier series of a function but it doesnt seem to be giving me anything near the graph of the original fuction.

t = -pi: 0.0001 : pi
total = 0.5

for n = 1:1:100
    an = -1*((-1)^n)+1 /pi*((n)^2);
    bn = -exp(1)*n*((-1)^n) - pi*n*((-1)^n) + 4*n*((-1)^n) - (4*n) + (exp(1)*n) /pi*n^2;
    total = total + an*cos(n*t) + bn*sin(n*t); 
end 

a0 = (-pi/2)+4+exp(1);
total = total*a0;
plot(t,total)

[David Goodmanson]

Hi Rohan,

you should take a close look at the expressions for an and bn because there appear to be errors. Such as the + sign in an or the very last part of an and bn which multiplies by n^2 but may be intending to divide by n^2

[Rohan Sabherwal]

I have tried to change it but keep getting something completely off, I tried looking over my working out for the fourier series and it seems to be okay.

[Bjorn Gustavsson]

Calculate and save the Fourier coefficient for all n and plot them - that way you can check that they behave in the way you expect/intend.

HTH

Answer 1

[Setsuna Yuuki.]

What is the waveform it is supposed to give? Did you try a simpler function?

I tried with this code: (Sawtooth wave)

t= 0:1e-3:5;
sumatoria = 0;
serie = 0;
    for n = 1:1:15
            serie=1/pi*1/n*sin(2*n*pi*t);
            sumatoria = serie+sumatoria;
    end
        sumatoria = 1/2-sumatoria;
        plot(t,sumatoria)