Create a diagram with 3 polynomials

I have defined 3 polynomials

P1 = [ 1 -2 -15]

P2 = [1 -7 12]

P3 = [1 1 -14 -24]

I want to generate a graph that will present the shape of all polynomials in range from -100 to 100 with specific description(the logarithmic axes)

How can I do it?

Answer 1

[Star Strider]

I am not certain wht you want with ‘logarithmic axes’ so this creates both as logarithmic —

P1 = [ 1 -2 -15];
P2 = [1 -7 12];
P3 = [1 1 -14 -24];

x = linspace(-100, 100, 250);
V1 = polyval(P1,x);
V2 = polyval(P2,x);
V3 = polyval(P3,x);

figure
plot(x, [V1;V2;V3])
Ax = gca;
Ax.XScale = 'log';                              % Logarithmic X-Axis
Ax.YScale = 'log';                              % Logarithmic Y-Axis
grid

Warning: Negative data ignored

It may be best to only have the x-axis be logarithmic, and if so, consider using logspace instead of linspace.

.

[Berkay]

If I change log as linear in here;

Ax.YScale = 'log';

Is Y-axis going to be linear and is X-axis still going to be log ?

[Star Strider]

The axes scaling is set for each axis, so the axis settings are independent of each other.

The default axis scaling for all axes is 'linear' so if you want the y-scale to be linear, remove the line that sets it to 'log'. You can of course set it to 'linear' if you want to.

[Berkay]

thanks a lot man!!

[Star Strider]

As always, my pleasure!