%% auteur : 30 setxunit 30 setyunit -2.1 2.1 setxrange -2.1 2.1 setyrange %tracerepere /O{0 0} def /cerc{O 2} def /A{90 cerc cpoint} def /B{40 cerc cpoint} def /C{-10 cerc cpoint} def /D{-60 cerc cpoint} def /E{-110 cerc cpoint} def cerc cercle [O A B] polygone [B C D E] ligne [O C] ligne B O A .3 (-) tripointarcarrow O B C .3 (=) tripointarcarrow C D E .3 (=) tripointarcarrow C D E .2 (-) tripointarcarrow [O A O B O C]{2 marked} dapply [A B B C C D D E]{1 marked} dapply $\alpha$ 0.3 0.6 cctexlabel $\beta$ 1.4 0.7 cctexlabel $\gamma$ 0.65 -1.2 cctexlabel