这个用来解二次函数，输入a,b,c就行了,基本形式，对称轴，顶点坐标，开口方向都知道了
program ercihanshu1;
var a,b,c,m1,m2,m3:real;
begin
writeln('input a,b,c');writeln;
readln(a,b,c);
m1:=b/(2*a);
m2:=(4*a*c-b*b)/(4*a);m3:=0-m1;
writeln('y=',a:5,'(x+(',m1:5,')fang+(',m2:5,')');
writeln('duichenzhou: ',m3:5);
writeln('dingdianzuobiao: (',m3:5,',',m2:5,')');
if a>0 then writeln('chao shang')
else writeln('chao xia'); end.
program ercihanshu1;
var a,b,c,m1,m2,m3:real;
begin
writeln('input a,b,c');writeln;
readln(a,b,c);
m1:=b/(2*a);
m2:=(4*a*c-b*b)/(4*a);m3:=0-m1;
writeln('y=',a:5,'(x+(',m1:5,')fang+(',m2:5,')');
writeln('duichenzhou: ',m3:5);
writeln('dingdianzuobiao: (',m3:5,',',m2:5,')');
if a>0 then writeln('chao shang')
else writeln('chao xia'); end.
