I cant seem to understand how to find the fundamental period from this exponential function. $$\large x(t)=\sum _{k=2}^{k=14} e^{ j k\frac{2\pi}{7} t}$$
I'd really appreciate any help, I cant find much anywhere
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Welcome to MSE. It is in your best interest that you type your questions (using MathJax) instead of posting links to pictures. – José Carlos Santos Feb 14 '21 at 10:59
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What would you get with $\sum^{k=14}_{k=1}$? What is the difference? – Henry Feb 14 '21 at 11:01
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I assume $j$ is an integer. Of course, if $j$ is a multiple of seven, then $x(t)$ is just the constant $13$. – Gerry Myerson Feb 14 '21 at 11:07
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Oh @GerryMyerson I am assuming that $j=\sqrt{-1}$ ... – ancient mathematician Feb 14 '21 at 11:09
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Of course, I should have seen that (but mathematicians usually use $i$ for that, not $j$). – Gerry Myerson Feb 14 '21 at 11:14
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I suspect this is from an engineering book. – ancient mathematician Feb 14 '21 at 11:18
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Is $x(t)=-\exp{\frac{2\pi j}{7}t}$ when we add up the GP? – ancient mathematician Feb 14 '21 at 11:22