the temporary solution to the problem has been found to be changing the wikitext to
;Analisi dell'errore <math display="block">E_k = x_k-1/a</math><math display="block">E_{k+1} = |x_{k+1}-\alpha| = f(x_k)-\alpha = (1-a)x_k+1-1/a</math><math display="block">= x_k-1/a-a x_k+1 = E_kk-a(x_k-1/a) = (1-a) E_k</math>e se <math>|1-a| <1</math> l'errore si riduce.