djonik2 uses crt;
var
y,a,b,c,d: Integer;
x: real;
begin
clrscr;
write('x=');readln(x);
write('a='); readln(a); 
write('b='); readln(b); 
write('c='); readln(c); 
write('d='); readln(d); 
y:= 1 / cos(x) + ln(abs(tan(x / 2)) + (a + b *x) / (c + d *x));
write('y=',y:0:4); 
end;
readln
end.
Наверное так...