1)
var x,s:real;
begin
readln(x);
s:=cos(x) - sin(x) + abs(x-7) + x*x - 1;
writeln (s)
end.
2)
var x,y,s:real;
begin
readln(x,y);
s:=(x+y)/2;
writeln(s)
end.
3)
var x,y:real;
begin
readln(x);
if x<0 then y:=x*x-5;<br>if x=0 then y:=3;
if x>0 then y:=x-3;
writeln(y)
end.