import graph3; import solids; size(0,150); currentprojection=perspective(0,0,10,up=Y); pen color=green; real alpha=250; real f(real x) {return x^2;} pair F(real x) {return (x,f(x));} triple F3(real x) {return (x,f(x),0);} path p=graph(F,0,1,n=10,operator ..)--cycle; path3 p3=path3(p); revolution a=revolution(p3,X,-alpha,0); render render=render(compression=0,merge=true); draw(surface(a),color,render); surface s=surface(p); draw(s,color,render); draw(rotate(-alpha,X)*s,color,render); draw(p3,blue); xaxis3(Label("$x$",1),xmax=1.25,dashed,Arrow3); yaxis3(Label("$y$",1),Arrow3); dot(Label("$(1,1)$"),(1,1,0),X+Y); arrow("$y=x$",(0.7,0.7,0),Y,0.75cm,red); arrow("$y=x^2$",F3(0.7),X,0.75cm,red); draw(arc(1.1X,0.3,90,90,3,-90),Arrow3);