Question

"cos(ω' T) is by definition equal to one"? Explanation wanted!

I can't wrap my head around it. I know each T is supposed to be one period. So it will always be 1, 2, 3 and so on periods; which then the COS will be at the top (1); however the ω is throwing me off. :S

Answer 1

hint:
by definition of period T, we have:
\[\Large \omega T = \omega \cdot \frac{{2\pi }}{\omega } = 2\pi \]

Answer 2

therefore:
\[\Large \cos \left( {\omega T} \right) = \cos \left( {2\pi } \right) = ...?\]

Answer 3

Ah, thank you! Understand! Of course! xP

Answer 4

:)