3_теориЛеготкина / выч методы / Лаба №1 / NASH_LOG

{Џа®Ја ¬¬  Ї®бв஥­Ёп Ї®«Ё­®¬  ‹ Ја ­¦ 
ђ Ў®вг ўлЇ®«­Ё«Ё ‹лвЄЁ­ Џ.‚., ‹г§Ё­ Њ.Њ. Ја Ђ’-01-2}
program Lagrang;
uses graph;
const n=8;
var x,y:array[0..n]of real;
i,j,t,m,b:integer;
w:real;

function lagr(x1:real):real;
var i,j:integer;
ln,q,p:real;
begin
ln:=0;
for i:=0 to n do
begin
q:=1;
p:=1;
for j:=0 to n do
begin
if not (i=j) then p:=p*(x1-x[j]);
if not (i=j) then q:=q*(x[i]-x[j]);
end;
ln:=ln+y[i]*p/q;
end;
lagr:=ln;
end;

begin
for i:=0 to n do x[i]:=-4+i;
y[0]:=0;
y[1]:=0;
y[2]:=1;
y[3]:=0;
y[4]:=0;
y[5]:=0;
y[6]:=-1;
y[7]:=0;
y[8]:=0;

m:=detect;
initgraph(m,b,'m:\bgi');
line(360,0,360,340);
line(0,170,720,170);
for i:=50 to 700 do
begin
t:=round(-170*(lagr(6*i/360-6))/4+170);
putpixel(i,t,3);
end;
readln;
closegraph;
end.