Kalmar "arcsin" aikin lissafi ne wanda ke nufin "arc sine". Arcsine na darajar da aka ba shi shine kusurwa wanda sine yayi daidai da wannan darajar, wanda aka bayyana a cikin radians. Wato, idan y = zunubi (x), to, arcsin (y) daidai yake da x.Alamar da ake amfani da ita don wakiltar aikin arcsine zunubi^-1, inda babban rubutun "-1" "yana nuna aikin juzu'i. Don haka, idan muna da y = zunubi (x), sannan x = zunubi ^ -1 (y).Misali, idan zunubi (x) = 0.5, to, arcsine na 0.5 yana daidai da 30. digiri ko π/6 radians, tun zunubi(30°) = zunubi(π/6) = 0.5. Saboda haka, zunubi^-1 (0.5) = 30° ko π/6 radians.