PROGRAM CHEB;

CONST
	n=20;
	bodu=100;
	pi=3.141592654;
	a=-10;
	b=10;

TYPE
   vektor = ARRAY [1..n] OF real;

FUNCTION func(x:real):real;
VAR
        t:real;
BEGIN
        t:=(x*(b-a)+(a+b))/2;
	func:=t*t*t*t*ln(10+abs(t))*cos(t);
END;

FUNCTION trans(x:real):real;
BEGIN
	trans:=(2*x-(a+b))/(b-a);
END;

FUNCTION c(j:integer):real;
VAR
	i:integer;
	y:real;
BEGIN
	y:=0;
	FOR i:=1 TO n DO
		y:=y+func(cos(pi/n*(i-0.5)))*cos(pi/n*(i-0.5)*(j-1));
	c:=2*y/n;
END;

PROCEDURE T(x:real; VAR tt:vektor);
VAR
	i:integer;
BEGIN
	tt[1]:=1;
	tt[2]:=x;
	FOR i:=3 TO n DO tt[i]:=2*x*tt[i-1]-tt[i-2];
END;


VAR
   i,j:integer;
   x,y,krok,x0,x1: real;
   ci,ti:vektor;
   fileout:text;

BEGIN
	ASSIGN(fileout,'vystup.dat');
	REWRITE(fileout);

	FOR i:=1 TO n DO ci[i]:=c(i);

	krok:=(b-a)/bodu;
	x:=a;

	FOR i:=1 TO bodu DO BEGIN
		T(trans(x),ti);
		y:=0.5*ci[1];
		FOR j:=2 TO n DO y:=y+ci[j]*ti[j];
    	        WRITELN(fileout,x,' ',y);
		x:=x+krok;
	END;

	CLOSE(fileout);
        WRITELN('hotovo');
	READLN;
END.