Untitled Metapost Sample #metapost-sandbox

main.mp

u := 1cm;
pickup pencircle scaled 0.6bp;

path fcurve;
fcurve := (0,-1.0u)
  .. (1u,-0.6u)
  .. (2u,-0.1u)
  .. (3u,0.5u)
  .. (4u,1.3u)
  .. (5u,2.4u);

%%%%%%%%%%%% Рисунок 1
beginfig(1);

drawarrow (-0.5u,0)--(6u,0);
label.bot("x",(6u,0));

draw fcurve withpen pencircle scaled 1bp;

pair A,B;
A := point 0 of fcurve;
B := point length(fcurve) of fcurve;

draw (0,0)--(0,ypart A) dashed evenly;
draw (5u,0)--(5u,ypart B) dashed evenly;
label.top("a",(0,0));
label.top("b",(5u,0));
dotlabel.lft("A",A);
dotlabel.rt("B",B);

numeric xn;
pair An;
xn := 2;
An := point 3 of fcurve;
draw (xn*u,0)--(xn*u,ypart An) dashed evenly;
label.top("x_n",(xn*u,0));
dotlabel.lft("A_n",An);

draw An--B;
pair Pxn; % x_{n+1}
Pxn := ((xpart An + (xpart B - xpart An)
         *(-ypart An)/(ypart B - ypart An)), 0);
drawdot Pxn;
label.top("x_(n+1)",Pxn);

endfig;

%%%%%%%%%%%% Рисунок 2
beginfig(2);

drawarrow (-0.5u,0)--(6u,0);
label.bot("x",(6u,0));
draw fcurve withpen pencircle scaled 1bp;
label.lft("y=f(x)",(0.2u,0.4u));

A := point 0 of fcurve;
B := point length(fcurve) of fcurve;
draw (0,0)--(0,ypart A) dashed evenly;
draw (5u,0)--(5u,ypart B) dashed evenly;
label.top("a",(0,0));
label.top("b",(5u,0));
dotlabel.lft("A",A);
dotlabel.rt("B",B);

pair C;
C := (3u,0);
drawdot C; label.top("C",C);

numeric xzero;
numeric xone;
pair Bzero,Bone;

xzero := 4.2;  Bzero := (4.2u,1.8u);
xone  := 3.4;  Bone  := (3.4u,0.9u);

draw (xzero*u,0)--Bzero dashed evenly;
draw (xone*u,0)--Bone  dashed evenly;
label.top("x_0",(xzero*u,0));
label.top("x_1",(xone*u,0));
dotlabel.rt("B_0",Bzero);
dotlabel.rt("B_1",Bone);

draw Bzero--Bone;

endfig;

%%%%%%%%%%%% Рисунок 3
beginfig(3);

drawarrow (-0.5u,0)--(6u,0);
label.bot("x",(6u,0));
draw fcurve withpen pencircle scaled 1bp;
label.lft("y=f(x)",(0.2u,0.4u));

A := point 0 of fcurve;
B := point length(fcurve) of fcurve;
draw (0,0)--(0,ypart A) dashed evenly;
draw (5u,0)--(5u,ypart B) dashed evenly;
label.top("a",(0,0));
label.top("b",(5u,0));
dotlabel.lft("A",A);
dotlabel.rt("B",B);

pair Caxis,Bn;
Caxis := (3u,0); drawdot Caxis; label.top("C",Caxis);
Bn := (4.1u,1.6u);
draw (4.1u,0)--Bn dashed evenly;
label.top("x_n",(4.1u,0));
dotlabel.rt("B_n",Bn);

draw Bn--Caxis;
pair PxnB;
PxnB := ((xpart Bn + (xpart Caxis - xpart Bn)
          *(-ypart Bn)/(ypart Caxis - ypart Bn)), 0);
drawdot PxnB;
label.bot("x_(n+1)",PxnB);

endfig;
end.