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Program lbr3;
uses crt;
const
  n=20; {Љ®«-ў®  в®зҐЄ}
  h=(pi/4)/n; { Ј}

function F(x, y: real): real;{---Џа ў п з бвм га ў­Ґ­Ёп---}
begin
  F:=y*sin(x)/cos(x) - x*x*cos(x);
end;

function sec(x: real): real;
begin
  sec:=(x*x*x/3+Pi/3)*cos(x);
end;

var
  i: integer;
  k: word;
  x: array[0..n] of real;
  y: array[0..n, 1..5]  of real; {’ Ў«Ёж }
  yy: real;
  w, a1, a2, b1, b2: real;
begin
  clrscr;
  GOTOXY(20,2);
  {writeln('ЏЋ‹“—…ЌЌ›… ‡ЌЂ—…Ќ€џ');}
  WRITELN;
  y[0, 1]:=sec(0); y[0, 2]:=sec(0); y[0, 3]:=sec(0); y[0, 4]:=sec(0);
  x[0]:=0;
  for k:=1 to n do x[k]:=x[0]+h*k;

  {----------- 1-© бв®«ЎЁЄ - ЊҐв®¤ ќ©«Ґа  (Їа®бв®©) -------------}
  for k:=0 to 2 do
    y[k+1, 1]:=y[k, 1]+h*F(x[k], y[k, 1]);

  {----------- 2-© бв®«ЎЁЄ - ЊҐв®¤ ќ©«Ґа  (¬®¤ЁдЁж) -------------}
  for k:=0 to 2 do begin
    y[k+1, 2]:=y[k, 2]+h*F(x[k], y[k, 2]);
    y[k+1, 2]:=y[k, 2]+h/2*(f(x[k], y[k, 2])+f(x[k+1], y[k+1, 2]));
  end;

  {----------- 3-© бв®«ЎЁЄ - ЊҐв®¤ ќ©«Ґа  (гв®з­Ґ­) -------------}
  for k:=0 to 2 do begin
    y[k+1, 3]:=y[k, 2]+h*F(x[k], y[k, 2]);
    {“в®з­пҐ¬}
    repeat
      yy:=y[k+1, 3];
      y[k+1, 3]:=y[k, 3]+h/2*(f(x[k], y[k, 3])+f(x[k+1], y[k+1, 3]));
    until y[k+1, 3]-yy<=0.00001
  end;

  {----------- 4-© бв®«ЎЁЄ - б ­ Ё«гз襩 w  ----------------------}
  for k:=0 to n-1 do begin
    w:=0.9{0.81875};
    a2:=w;  b2:=1/(2*w); b1:=b2;  a1:=1-w;
    y[k+1, 4]:=y[k, 4]+h*(a1+a2)*f(x[k], y[k, 4])+h*h*a2*b1*(y[k, 4]/sqr(cos(x[k]))+x[k]*x[k]*sin(x[k])-2*x[k]*cos(x[k]))+
    h*h*f(x[k],y[k,4])*sin(x[k])/cos(x[k]);
 end;

  {----------- 5-© бв®«ЎЁЄ - в®з­®Ґ аҐиҐ­ЁҐ ---------------------}
  for k:=0 to n do
    y[k, 5]:=sec(x[k]);


  {----------- ЊҐв®¤ ЊЁ«­  (¤«п ўбҐе бв®«ЎЁЄ®ў)--------------------}
  for i:=1 to 4 do {зҐвлॠбв®«ЎЁЄ }
    for k:=4 to n do begin
      {ЏаҐ¤Ї®«®¦ЁвҐ«м­®Ґ §­ зҐ­ЁҐ:}
      y[k, i]:=y[k-4, i]+4*h/3*(2*f(x[k-3], y[k-3,  i]) -
                                  f(x[k-2], y[k-2,  i]) +
                                2*f(x[k-1], y[k-1,  i]));
      {“в®з­пҐ¬:}
      y[k, i]:=y[k-2, i] + h/3*(  f(x[k-2], y[k-2,  i]) +
                                4*f(x[k-1], y[k-1,  i]) +
                                  f(x[k],   y[k,  i]));
    end;
    textcolor(lightmagenta);
  WriteLn('N':3, '  ', 'Џа®бв®©':12, '  ', 'Њ®¤ЁдЁжЁа':12, '  ', '“в®з­Ґ­­л©':12, '  ', '‘ ­ Ё«гз襩':12, '  ', '’®з­®Ґ':12);
  WriteLn(' ':3, '  ', 'ќ©«Ґа':12, '  ', 'ќ©«Ґа':12, '  ', 'ќ©«Ґа':12, ' ', '®¬ҐЈ ':12, '  ', '§­ зҐ­ЁҐ':12);
  writeln;textcolor(white);
  for i:=0 to n do
  begin if i>15 then
  textcolor(i-10) else textcolor(i);
    WriteLn(i:3, '  ', y[i, 1]:12:10, '  ', y[i, 2]:12:10,  '  ', y[i, 3]:12:10, '  ',
            y[i, 4]:12:10, '  ', y[i, 5]:10:10);
            end;
 while not keypressed do;
end.