fourier series

Thread Starter


Joined Jul 10, 2011
I am trying to solve fourier series problems. i have few confusions about that..

1) x(t) =\(\sum c_x(k)e ^{jkwt}\)

where as \(c_x(k) = \int_T x(t) e^{-jwt} dt \)

My question is that when which equation do we use to plot the graph.
and how do we take the values for the graph. Is it BODE PLOTS or is it simply plugging in the values.

suppose i havethis expression
\(c_x(k)= A/2 \frac {cos(k\prod-1)}{k\prod}^2\)

\(or\ i\ have\ c_x(k)= A/2 \frac {sinc(k\prod-1)}{k\prod}^2\)

then how can i graph this equation for \(c_1\ ,\ c_2\ ,\ ......\)


Joined Nov 25, 2009
Are these equations for \(c_x(k)\) correct? The multiplication symbol has no argument in either of them. It refers to the product of what?

Thread Starter


Joined Jul 10, 2011
The question i have is f(t)= \(A\ cos200\pi t\)
and this is the expression for fourier series \(x(t) = \sum^{+\infty}_{k=-\infty}c_ke^{j2wkt}\)

i got the following solution for fourier coefficients

\(now\ for\ c_k\ =-\frac{1}{4}\frac{Sin(\pi +k)(0.5)}{(\pi+k)}-\frac{1}{4}\frac{Sin(\pi - k)0.5}{\pi-k}-\frac{1}{4}\frac{Sin(\pi+k)1.5}{\pi+k}-\frac{1}{4}\frac{Sin(\pi-k)1.5}{\pi-k}\)

Now my prof asks me to sketch the fourier series coefficients i.e. \(c_k\ for\ k=\ 1,2,3,....\)

I wanna know how to sketch the result i got