beginfig(1);
numeric u;
u=2.5cm ;
drawarrow (-1.2*u,0)--(1.2*u,0);
drawarrow (0,-1.2*u)--(0,1.2*u);
draw fullcircle scaled 5cm;
draw (0,0)--(u,(sind(45)/cosd(45))*u);
draw (0,sind(45)*u)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (cosd(45)*u,0)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (u,-1.3*u)--(u,1.3*u);
drawarrow (0.12*u,0)..(0.12*cosd(45)*u,0.12*sind(45)*u);
dotlabel.llft(btex $0$ etex, (0,0));
dotlabel.lrt(btex $I$ etex, (u,0));
dotlabel.ulft(btex $J$ etex, (0,u));
dotlabel.lft(btex $\sin x$ etex, (0,sind(45)*u));
dotlabel.bot(btex $\cos x$ etex, (cosd(45)*u,0));
dotlabel.rt(btex $\tan x$ etex , (u,(sind(45)/cosd(45))*u));
label.top(btex $x$ etex,(cosd(45)*u,sind(45)*u));
endfig;

beginfig(2);
numeric u;
u=2.5cm ;
drawarrow (-1.2*u,0)--(1.2*u,0);
drawarrow (0,-1.2*u)--(0,1.2*u);
draw fullcircle scaled 5cm;
draw (0,0)--(u,(sind(45)/cosd(45))*u);
draw (-cosd(45)*u,sind(45)*u)--(u,-(sind(45)/cosd(45))*u);
draw (-cosd(45)*u,sind(45)*u)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (cosd(45)*u,0)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (-cosd(45)*u,0)--(-cosd(45)*u,sind(45)*u) dashed evenly;
draw (u,-1.3*u)--(u,1.3*u);
drawarrow (0.12*u,0)..(0.12*cosd(45)*u,0.12*sind(45)*u);
drawarrow (0.3*u,0){up}..(0,0.3*u)..(-0.3*cosd(45)*u,0.3*sind(45)*u);
dotlabel.llft(btex $0$ etex, (0,0));
dotlabel.lrt(btex $I$ etex, (u,0));
dotlabel.ulft(btex $J$ etex, (0,u));
dotlabel.ulft(btex $\sin(x)$ etex, (0,sind(45)*u));
dotlabel.bot(btex $\cos(x)$ etex, (cosd(45)*u,0));
dotlabel.bot(btex $-\cos(x)$ etex, (-cosd(45)*u,0));
dotlabel.rt(btex $\tan(x)$ etex , (u,(sind(45)/cosd(45))*u));
dotlabel.rt(btex $-\tan(x)$ etex , (u,-(sind(45)/cosd(45))*u));
label.top(btex $x$ etex,(cosd(45)*u,sind(45)*u));
label.top(btex $\pi-x$ etex,((-cosd(45)-0.1)*u,sind(45)*u));
endfig;

beginfig(3);
numeric u;
u=2.5cm ;
drawarrow (-1.2*u,0)--(1.2*u,0);
drawarrow (0,-1.2*u)--(0,1.2*u);
draw fullcircle scaled 5cm;
draw (-cosd(45)*u,-sind(45)*u)--(u,(cosd(45)/sind(45))*u);
draw (cosd(45)*u,0)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (-cosd(45)*u,0)--(-cosd(45)*u,-sind(45)*u) dashed evenly;
draw (0,-sind(45)*u)--(-cosd(45)*u,-sind(45)*u) dashed evenly;
draw (0,sind(45)*u)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (u,-1.3*u)--(u,1.3*u);
drawarrow (0.12*u,0)..(0.12*cosd(45)*u,0.12*sind(45)*u);
drawarrow (0.3*u,0){up}..(0,0.3*u)..(-0.3*cosd(45)*u,-0.3*sind(45)*u);
dotlabel.ulft(btex $0$ etex, (0,0));
dotlabel.lrt(btex $I$ etex, (u,0));
dotlabel.ulft(btex $J$ etex, (0,u));
dotlabel.lft(btex $\sin(x)$ etex, (0,sind(45)*u));
dotlabel.rt(btex $-\sin(x)$ etex, (0,-sind(45)*u));
dotlabel.bot(btex $\cos(x)$ etex, (cosd(45)*u,0));
dotlabel.top(btex $-\cos(x)$ etex, (-cosd(45)*u,0));
dotlabel.rt(btex $\tan(x)$ etex , (u,(sind(45)/cosd(45))*u));
label.top(btex $x$ etex,(cosd(45)*u,sind(45)*u));
label.bot(btex $\pi+x$ etex,((-cosd(45)-0.1)*u,-sind(45)*u));
endfig;

beginfig(4);
numeric u;
u=2.5cm ;
drawarrow (-1.2*u,0)--(1.2*u,0);
drawarrow (0,-1.2*u)--(0,1.2*u);
draw fullcircle scaled 5cm;
draw (0,0)--(u,(cosd(45)/sind(45))*u);
draw (0,0)--(u,-(cosd(45)/sind(45))*u);
draw (cosd(45)*u,-sind(45)*u)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (0,-sind(45)*u)--(cosd(45)*u,-sind(45)*u) dashed evenly;
draw (0,sind(45)*u)--(cosd(45)*u,sind(45)*u) dashed evenly;
draw (u,-1.3*u)--(u,1.3*u);
drawarrow (0.12*u,0)..(0.12*cosd(45)*u,0.12*sind(45)*u);
drawarrow (0.12*u,0)..(0.12*cosd(45)*u,-0.12*sind(45)*u);
dotlabel.ulft(btex $0$ etex, (0,0));
dotlabel.lrt(btex $I$ etex, (u,0));
dotlabel.ulft(btex $J$ etex, (0,u));
dotlabel.lft(btex $\sin(x)$ etex, (0,sind(45)*u));
dotlabel.lft(btex $-\sin(x)$ etex, (0,-sind(45)*u));
dotlabel.llft(btex $\cos(x)$ etex, (cosd(45)*u,0));
dotlabel.rt(btex $\tan(x)$ etex , (u,(sind(45)/cosd(45))*u));
dotlabel.rt(btex $-\tan(x)$ etex , (u,-(sind(45)/cosd(45))*u));
label.top(btex $x$ etex,(cosd(45)*u,sind(45)*u));
label.bot(btex $-x$ etex,(cosd(45)*u,(-sind(45)-0.05)*u));
endfig;
end