C. Y. Bosch-m, Ostensifs et sensibilité aux ostensifs dans l'activité mathématique, Recherche en Didactique des Mathématiques, V, vol.19, issue.1, pp.77-123, 1999.

. Planip, 1, y=0..sqrt(1-x^2),color=green): 15 > PlanIN:=plot3d([x,y,-y],x=-1..1, y=-sqrt(1-x^2)..0,color=green): 16 > Cz2:=plot3d({[t,sqrt(1-t^2),s], [t,-sqrt(1-t^2),s]},t=-1..1,s=0..sqrt(1-t^2),color=red): 17 > Cy2, color=navy): 18 > display, pp.3-3

>. Vq, Int(1,z=0..y),y=0..sqrt(1-x^2)),x=-1

>. Vq, (1,z=0..y),y=0..sqrt(1-x^2)),x=-1

>. Vq, (1,z=0..y),y=0..sqrt(1-x^2)),x=-1

>. Vq, =8*int(int(int(1,z=0..y),y=0..sqrt(1-x^2)),x=-1

>. S1, sin(t),z],t=0..2*Pi, z=-sin(t)..sin(t, color=blue), p.3