This is an example where the length of the Cosine Series is increased and compared with the Cosine Transform which has an infinite domain. [br]The Fourier Cosine Transform of a unit step pulse is [math]H\left(1-x\right)\Longrightarrow\frac{2}{\pi\omega}sin\left(\omega\right)[/math] and the Cosine Series is [math]A_n=\frac{2}{n\pi}\sin\left(n\pi\frac{x}{L}\right)[/math] . As the domain length increases [math]\frac{n\pi}{L}\longrightarrow\omega[/math] and [math]\frac{L}{\pi}A_n\longrightarrow F_{c\left(\omega\right)}[/math]. This animation illustrates the comparison as the length [math]L[/math] is animated.