We have just received a question by email:
I got a question about the writing in wiris. How can i program the following formular: f(x)= x2 +1 | x < 1,5 and x > 1? How can i set the domain for x? Is there an adequate sign for "|"? There ist no help online.
We offer you several options:

, en tot cas cal usar l'oerator lògic 'i'
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