How to change color in Graph (jet)

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Niklas Kurz
Niklas Kurz 2021-1-17
回答： Walter Roberson 2021-1-17
I copied and pasted the following code that describes a Fourier Series
% Define domain
dx = 0.001;
L = pi;
x = (-1+dx:dx:1)*L;
n = length(x); nquart = floor(n/4);
% Define function
f = x;
plot(x,f,'-k','LineWidth',1.5), hold on
% Compute Fourier series
CC = jet(20);
A0 = sum(f.*ones(size(x)))*dx;
fFS = A0/2;
for k=1:20
A(k) = sum(f.*cos(pi*k*x/L))*dx; % Inner product
B(k) = sum(f.*sin(pi*k*x/L))*dx;
fFS = fFS + A(k)*cos(k*pi*x/L) + B(k)*sin(k*pi*x/L);
plot(x,fFS,'-','Color',CC(k,:),'LineWidth',1.2)
end
legend('Function: f(x) = x',...
'Terms: N = 20','Interpreter','latex','Fontsize',16,...
'Location','northwest')
I noticed, that the color of "Terms" in legend is always blue (so k = 1). However, I want it to be the color of the kth Function, im my case k = 20.
How to achieve that? A common problem with coppied function.

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采纳的回答

Walter Roberson
Walter Roberson 2021-1-17
Ran in:
% Define domain
dx = 0.001;
L = pi;
x = (-1+dx:dx:1)*L;
n = length(x); nquart = floor(n/4);
% Define function
f = x;
h1 = plot(x,f,'-k','LineWidth',1.5);
hold on
% Compute Fourier series
CC = jet(20);
A0 = sum(f.*ones(size(x)))*dx;
fFS = A0/2;
for k=1:20
A(k) = sum(f.*cos(pi*k*x/L))*dx; % Inner product
B(k) = sum(f.*sin(pi*k*x/L))*dx;
fFS = fFS + A(k)*cos(k*pi*x/L) + B(k)*sin(k*pi*x/L);
hk = plot(x,fFS,'-','Color',CC(k,:),'LineWidth',1.2);
end
legend( [h1, hk], {'Function: f(x) = x',...
'Terms: N = 20'}, 'Interpreter', 'latex', 'Fontsize', 16,...
'Location', 'northwest')

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