import solids;
size(7.5cm,0);
viewportmargin=3mm;
currentprojection=orthographic((9,6,4));
pen color=orange+yellow;

real f(real x) {return sqrt(x);}
pair F(real x) {return (x,f(x));}

real a=1;
path p=graph(F,0,a^2,n=10,operator ..)--(0,a)--cycle;
path3 p3=rotate(-90,Y)*path3(p);

render render=render(compression=0,merge=true);

real alpha=260, alphar=pi/2+alpha*pi/180;
draw(surface(revolution(p3,Z,0,alpha)),color,render);

surface s=rotate(-90,Y)*surface(p);
draw(s,color,render);
draw(rotate(alpha,Z)*s,color,render);

draw(p3,.8bp+orange);

xaxis3(Label("$x$",1),xmax=a+.5,Arrow3);
yaxis3(Label("$y$",1),ymax=a+.5,Arrow3);
zaxis3(Label("$z$",1),zmax=a^2*1.3,Arrow3);

draw((a*cos(alphar),a*sin(alphar),a^2)--(0,0,a^2)--(0,a,a^2),dashed);
draw(arc(a^2*Z,r=a/2,90,90,90,90+alpha,CW),Arrow3);
draw(arc(0Z,r=a,90,90+alpha,90,90,CCW),dashed,Arrow3);