Why am not getting any graph?

clc;
clear;
syms p;
x = 13.61015;
y = 13257;
a = 5.14;
b = 11.47;
err1 = 0.000001;
f = (x^3 + p^2*x^2 - 10)*sin(x) - y == 0;
i=0;
if ((x^3 + a^2*x^2 - 10)*sin(x) - y) * ((x^3 + b^2*x^2 - 10)*sin(x) - y) > 0
    disp ('Wrong Interval');
    return
else 
    c = (a+b)/2;
    err = abs(a-b);
end
while err > err1
    if ((x^3 + a^2*x^2 - 10)*sin(x) - y) * ((x^3 + c^2*x^2 - 10)*sin(x) - y) < 0
        b=c;
        i=i+1;
    else 
        a=c;
    end
    c = (a+b)/2;
    err = abs(c-b);
    root = c;
end
y1 = (x^3 + c^2*x^2 - 10)*sin(x);
x1 = 0:20;
figure
plot(x1,y1);
disp (i);
disp (c);
disp (err);

Answer 1

[Voss]

Do you mean for y1 to be calculated from x1, rather than from x?

x1 = 0:20;
y1 = (x1.^3 + c^2*x1.^2 - 10).*sin(x1);

To answer your question: you don't see a plot because y1 is a scalar, which happens because x is a scalar. A plot of a single point with no data marker cannot be seen.

[Nikolas]

thank you.

[Voss]

You're welcome!

Answer 2

[KSSV]

clc; clear all ;
clc;
clear;
syms p;
x = 13.61015;
y = 13257;
a = 5.14;
b = 11.47;
err1 = 0.000001;
f = (x^3 + p^2*x^2 - 10)*sin(x) - y == 0;
i=0;
if ((x^3 + a^2*x^2 - 10)*sin(x) - y) * ((x^3 + b^2*x^2 - 10)*sin(x) - y) > 0
    disp ('Wrong Interval');
    return
else 
    c = (a+b)/2;
    err = abs(a-b);
end
while err > err1
    if ((x^3 + a^2*x^2 - 10)*sin(x) - y) * ((x^3 + c^2*x^2 - 10)*sin(x) - y) < 0
        b=c;
        i=i+1;
    else 
        a=c;
    end
    c = (a+b)/2;
    err = abs(c-b);
    root = c;
end
x1 = 0:20;
y1 = (x1.^3 + c^2*x.^2 - 10).*sin(x1);

figure
plot(x1,y1);

disp (i);

    14

disp (c);

    8.3215

disp (err);

   7.5459e-07

[Nikolas]

thank you