function wave_packet_cosines
% Figure 4.12
hold off
clc
dk=input('Insert dk = 0.5 = ');
nmax=input('Insert the number of terms nmax = 100 = ');
k1 = input('Insert initial k_0 = 100 = ');
x=[-5:.001:5]; nx=length(x);
% To plot the graph on [-1,1], change the interval and 
% the x-axis definitions below
%x=[-1:.001:1]; nx=length(x);
kn=[k1:dk:k1+nmax*dk];
s=0;
for i=1:nmax
   s=s+cos(kn(i)*x*pi)/nmax;
end
plot(x,s,'-k','linewidth',1.2)
ylabel('$f(x)$','Interpreter','latex','fontsize',36)
xlabel('$x$','Interpreter','latex','fontsize',36)
axis([-5 5 -1 1])
%axis([-1 1 -1 1])
set(gca,'FontSize',36)
set(gca,'Ytick',[-1:.50:1],'linewidth',1.6)
set(gca,'Xtick',[-5:1:5],'linewidth',1.6)
%set(gca,'Xtick',[-1:.5:1],'linewidth',1.6)
set(gcf, 'Units','centimeters','Papersize',[36,36])
set(gcf, 'Units','centimeters','Position',[3 3 24 20]) 
% Try the corresponding sine series and change parameters