Hello juliak Originally Posted by
juliak OK. I now know what kpi is: $\displaystyle k \pi$. But I still don't see where $\displaystyle \sin x \ne 0$ is relevant in your original post.
However, what you have written here is easy to understand. If $\displaystyle \sin x \ne 0$, then $\displaystyle x$ cannot be a multiple of $\displaystyle \pi$. (Since the sine of all multiples of $\displaystyle \pi$ is zero.) In other words: $\displaystyle \sin x \ne 0$
$\displaystyle \Rightarrow x \ne k\pi$, where $\displaystyle k$ is an integer
$\displaystyle \Rightarrow x \ne 0 + k\pi$
Have we cleared all this up now?
Grandad