Here's the question you clicked on:
DeleonBRRJ
Where the periodic function assumes its extreme values and that these values are?
\[F(x)=e^{Sin \frac{ X }{ 2 }}\]
The function will have its peaks when sinx = 1 or -1. Using a unit circle, you can see that they occur at pi/2 + pix. But since the quantity is halved, you double this number and get: pi + 2pix
Isn't it clearer to write pi + 2pi*k, where k is an integer?