%
% C.Talarico
% file: plotquadratic.m
%

clear all; close all; clc;
syms x;

figure
hold on
a = 2; b = 7; c = 3;
y = a*x^2 + b*x + c;
r = solve(y == 0, x);
r_12 = vpa(r)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
h1 = ezplot(y);
set(h1, 'color','m','linewidth',1);
y1_str = char(y);

a= -2; b= -7; c= -3;
y = a*x^2 + b*x + c;
r = solve(y == 0, x);
r_12 = vpa(r)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
f1 = ezplot(y);
set(f1, 'color','b','linewidth',1);
y2_str = char(y);

ax = gca;
set(ax,'Fontsize',14, 'FontName', 'Monospace', 'Fontweight', 'Normal');
xlabel('x', 'Fontsize', 16);
title('y = a x^2 + b x + c', 'Fontsize', 18);
ylim([-50 +50]);
legend(y1_str, y2_str, 'location','Best');

line([-10 10],[0 0],'color','r','LineStyle',':', 'linewidth',2);
line([0 0],[-50 +50], 'color', 'k', 'LineStyle',':', 'linewidth',2);

hold off;
disp('---------------------------------');


figure
hold on;
a = -2; b = 7; c = -3;
y = a*x^2 + b*x + c;
r = solve(y==0, x);
r_12 = vpa(r)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
ezplot(y);
h2 = ezplot(y);
set(h2, 'color','m','linewidth',1);
y1_str = char(y);

a= 2; b= -7; c= 3;
y = a*x^2 + b*x + c;
r = solve(y == 0, x);
r_12 = vpa(r)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
f2 = ezplot(y);
set(f2, 'color','b','linewidth',1);
y2_str = char(y);

ax = gca;
set(ax,'Fontsize',14, 'FontName', 'Monospace', 'Fontweight', 'Normal');
xlabel('x', 'Fontsize', 16);
title('y = a x^2 + b x + c', 'Fontsize', 18);
ylim([-50 +50]);
legend(y1_str, y2_str, 'location','Best');

line([-10 10],[0 0],'color','r','LineStyle',':', 'linewidth',2)
line([0 0],[-50 +50], 'color', 'k', 'LineStyle',':', 'linewidth',2);

hold off;
disp('---------------------------------');


figure
hold on
a = 2; b = 7; c = -3;
y = a*x^2 + b*x + c;
r = solve(y == 0, x);
r_12 = vpa(r,4)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
h1 = ezplot(y);
set(h1, 'color','m','linewidth',1);
y1_str = char(y);

a= -2; b= -7; c= 3;
y = a*x^2 + b*x + c;
r = solve(y == 0, x);
r_12 = vpa(r,4)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
f1 = ezplot(y);
set(f1, 'color','b','linewidth',1);
y2_str = char(y);

ax = gca;
set(ax,'Fontsize',14, 'FontName', 'Monospace', 'Fontweight', 'Normal');
xlabel('x', 'Fontsize', 16);
title('y = a x^2 + b x + c', 'Fontsize', 18);
ylim([-50 +50]);
legend(y1_str, y2_str, 'location','Best');

line([-10 10],[0 0],'color','r','LineStyle',':', 'linewidth',2);
line([0 0],[-50 +50], 'color', 'k', 'LineStyle',':', 'linewidth',2);

hold off;
disp('---------------------------------');


figure
hold on
a = 2; b = -7; c = -3;
y = a*x^2 + b*x + c;
r = solve(y == 0, x);
r_12 = vpa(r,4)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
h1 = ezplot(y);
set(h1, 'color','m','linewidth',1);
y1_str = char(y);

a= -2; b= 7; c= 3;
y = a*x^2 + b*x + c;
r = solve(y == 0, x);
r_12 = vpa(r,4)
Dy = diff(y,x);
mm = solve(Dy == 0, x);
x_minmax = vpa(mm)
f1 = ezplot(y);
set(f1, 'color','b','linewidth',1);
y2_str = char(y);

ax = gca;
set(ax,'Fontsize',14, 'FontName', 'Monospace', 'Fontweight', 'Normal');
xlabel('x', 'Fontsize', 16);
title('y = a x^2 + b x + c', 'Fontsize', 18);
ylim([-50 +50]);
legend(y1_str, y2_str, 'location','Best');

line([-10 10],[0 0],'color','r','LineStyle',':', 'linewidth',2);
line([0 0],[-50 +50], 'color', 'k', 'LineStyle',':', 'linewidth',2);

hold off;
disp('---------------------------------');