Kalmar "arc cosine" tana nufin aikin trigonometric inverse wanda ke ba da kusurwa wanda cosine lambar da aka bayar. Ana nuna shi a matsayin "arccos" ko "cos^-1" kuma shine sabanin aikin cosine. Ƙwaƙwalwar baka na lamba x ita ce kwana wanda cosine x. Sakamakon aikin arc cosine koyaushe shine kwana tsakanin 0 da π radians (ko 0 da 180 digiri), wanda ya haɗa da.
