MathJax, my code doesn't seem to work completely fine, can anybody have a look?

Question

I'm having some weird problem with MathJax. Everything on my site works fine, every MathJax snippet, except some subpage. I'm making a website about functions and their transformations in Polish. When I'm trying to perform the code, it's like it breaks performing in the middle. I'm attaching a link to the image with the code and the results: I'm sure I've checked the code in detail... It's really important for me to work fine! Thanks in advance.

The code:

Funkcja $f(k*x)$ rozciąga się w poziomie dla $k>1 \lor k<-1$, zaś dla $ 1<k \land k<-1 $ jest ona ściśnięta w poziomie.
Funkcja $k*f(x)$ ściska się w pionie dla $k>1 \lor k<-1$, zaś dla $ 1<k \land k<-1$ jest ona rozciągnięta w pionie.
Warto zaznaczyć, iż gdy $k$ jest ujemne, to funkcja dodatkowo obraca się symetrycznie wokół osi OX dla $k*f(x)$ i wokół osi OY dla $f(k*x)$.

Oh, now I got it... The code was broken in the same place where "1< k" is placed, and Firefox reads is as a HTML tag, and this made the MathJax code run not properly. Question can be closed

Answer 1

The problem is in the browser processing the (unescaped) < (which makes the HTML invalid) before MathJax gets to it.

Long story short, try $k > 1 \lor k<-1$ to be safe.