How to plot multiple graph
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Hello all
I am going to plot f= sin(5x)/x^3 and its derivative f '(x) within the domain x ∈[0.1,0.4]using semilogy plot.
6 Comments
Answers (2)
Jon
on 21 Sep 2020
I don't have the symbolic toolbox, but I could get your code to work by modifying as follows. Note I did not include the line syms x as I don't have the symbolic toolbox.
x=logspace(0.1,0.4);
f =sin(5*x)./(x.^3);
Df= gradient(f)./gradient(x);
semilogx(x,f,'g')
hold on
semilogx(x,Df,'r')
grid
2 Comments
Jon
on 21 Sep 2020
The key line is
Df= gradient(f)./gradient(x)
This gives a simple numerical approximation to the derivative.
You can see what the gradient function does by typing doc gradient on the command line.
Ameer Hamza
on 21 Sep 2020
You are using the symbolic variables incorrectly. Check this code
% clc; clear all; close all;
syms x
f(x)=sin(5*x)./(x.^3);
Df = diff(f,x);
xv = logspace(0.1,0.4);
semilogx(xv, f(xv), 'g')
hold on
semilogx(xv, Df(xv), 'r')
grid
3 Comments
Image Analyst
on 21 Sep 2020
And you might add a legend so you know what color is what.
legend('Original Signal', 'Derivative', 'Location', 'northeast');
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