Can you help me to plot the derivative of the function.

I have a code matlab:

k = 3;

N = 2500;

L = 250;

B = L/N ;

dn = 1/L;

n0 = 0.1;

n = dn : dn : N*dn;

phi = 2*pi*rand(size(n));

Amp1 = sqrt(dn)*(2^k)*(1e-3)*(n0./n);

x = 0:B:L-B;

hx = zeros(size(x));

for i=1:length(x)

hx(i) = sum(Amp1.*cos(2*pi*n*x(i)+ phi));

end

Can you help me to plot the derivative of the function hx(i).

Thank you so much. Have a good day.

Answer 1

[KALYAN ACHARJYA]

plot(diff(hx));

https://in.mathworks.com/help/matlab/ref/diff.html

[Happy Dumbo]

Thank you so much.

Excuse me, can you help me explain why the frequency of diff(hx) is denser than hx when I plot 2 graph, please ?

[KALYAN ACHARJYA]

If diff, each element is subtracted from the precious one, its not impacted in other ways.

>> A=randi(10,[1,10])
A =
     1     3     6    10    10     2    10    10     5     9
>> diff(A)
ans =
     2     3     4     0    -8     8     0    -5     4

See the df/dx definition, If h is infinitesimally small, then becomes f(x+h)-f(x)

[Happy Dumbo]

Thank you very much.

Have a good day.