Tigni

Deg tenzeggit, Tigni neɣ Tizwi d akat n tuẓẓma n twinest neɣ n tuzza. Ma d tigni n kra n umtiweg iga d tizzungeltis. Tuzza tla (tesɛa) tigni n 0, ma d tagra timifedg usdid ila tigni n 1.

Tigni n uzunglay.

Amtiweg amazzay ila amili agaman i wemsel neɣ i tigni,Asemdu n webralmas isselfaw-d tamerruzt tasbegsant.
S tusnak, tigni tettwafek-d s:

$f={\mbox{ver}}(o\!\varepsilon )=2\sin ^{2}\left({\frac {o\!\varepsilon }{2}}\right)=1-\cos(o\!\varepsilon )={\frac {a-b}{a}}\approx {\frac {15\pi }{4GT^{2}\rho }}\ ;$

anda $a$ d $b$ gan d izenzaren n waggad d usafaylu n umtiweg, s umdafar, d $o\!\varepsilon \,\!$ iga d ’aɣwali uɣmir. Tamawaẓt d taɣbelt deg tegʷnit n umtiweg amengi seg tneẓẓi tayiwnit, dɣa tga d tasɣent n imezgi aldayan aseddayan, $G$, n tallit n tuzzya $T$ yakk n tneẓẓi $\rho$.
Akken i tella daɣen tigni tis snat, f' (tikwal tettwasezmel « n ») :

$f'=\tan ^{2}\left({\frac {o\!\varepsilon }{2}}\right)={\frac {1-\cos(o\!\varepsilon )}{1+\cos(o\!\varepsilon )}}={\frac {a-b}{a+b}}$.