semilogy plotting in domain

hello evryone

I hope someone can help me doing my project, as I am very new to Matlab; I am going to plot by f'j , approxomated by three methods. I neeed to plot it by semilogy in domain x ∈[0.1,0.4]. I am not sure if the plot that is given by my code is right; can someone give me some tips?

clc; clear all;close all;
f = @(x) sin(5*x)./x.^3;
h = 0.0005;
x = 0.1:h:0.4;                 
n = length(x);
y=f(x);
dyforward = zeros(n,1); 
dycentral = zeros(n,1);
dyforthcent = zeros(n,1);
for i=2:n-1
    dyforward(i) = (y(i+1)-y(i))/h;
    dycentral(i) = (y(i+1)-y(i-1))/(2*h);
end
for i=3:n-3
      dyforthcent (i)=(-y(i+2)+8*y(i+1)-8*y(i-1)+y(i-2)).*(1/12./h);
end

figure;
grid on;
hold on;
semilogy(x,y,'r');
semilogy(x(2:end-1), dyforward(2:end-1),'linewidth',1);
semilogy(x(2:end-1), dycentral(2:end-1),'linewidth',2);
semilogy(x(3:end-3), dyforthcent(3:end-3),'linewidth',3);
legend('y', 'dyforward', 'dycentral', 'dyforthcent')