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. Amtiweg amazzay ila amili agaman i wemsel neɣ i tigni,Asemdu n webralmas isselfaw-d tamerruzt tasbegsant. S tusnak, tigni tettwafek-d s: f = ver ( o ε ) = 2 sin 2 ⁡ ( o ε 2 ) = 1 − cos ⁡ ( o ε ) = a − b a ≈ 15 π 4 G T 2 ρ ; {\displaystyle 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 {\displaystyle a} d b {\displaystyle b} gan d izenzaren n waggad d usafaylu n umtiweg, s umdafar, d o ε {\displaystyle 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 {\displaystyle G} , n tallit n tuzzya T {\displaystyle T} yakk n tneẓẓi ρ {\displaystyle \rho } . Akken i tella daɣen tigni tis snat, f' (tikwal tettwasezmel « n ») : f ′ = tan 2 ⁡ ( o ε 2 ) = 1 − cos ⁡ ( o ε ) 1 + cos ⁡ ( o ε ) = a − b a + b {\displaystyle f'=\tan ^{2}\left({\frac {o\!\varepsilon }{2}}\right)={\frac {1-\cos(o\!\varepsilon )}{1+\cos(o\!\varepsilon )}}={\frac {a-b}{a+b}}} . == Ẓeṛ daɣen ==