We have to integers $a,b$. I need to show that if $a$ and $b$ are coprimes then the set of prime numbers of kind $ak+b$ is infinite.
How could I show it ? I know how to do that for $4k+3$ or $4k+1$, but I have no idea how to get the general answer.
We have to integers $a,b$. I need to show that if $a$ and $b$ are coprimes then the set of prime numbers of kind $ak+b$ is infinite.
How could I show it ? I know how to do that for $4k+3$ or $4k+1$, but I have no idea how to get the general answer.
As the comments have mentioned, this is Dirichlet's theorem on arithmetic progressions and requires some fairly involved analytic number theory. There is probably not a simple proof.
You can find an English translation of Dirichlet's original paper online, but I haven't checked the translation for accuracy, relevance, or legibility (because it is beyond me!)