How to plot a function in 2d with function from 3d

Hey!

I am finished with a and b but i need much help with c. Down below is the information from the exercise.

Down below is my script for a and b but i do not know if the script that I have for C i correct.

%% Exercise 2.a
clear
clf
clc
k=1
L=6
x=linspace(0,L);
 
fplot(@(x) (((2.*k)./L).*x), [0,(L/2)])
hold on
fplot(@(x) (((2.*k)./L).*(L-x)), [(L/2),L])
%% Exercise 2.b
clear
clf
clc
k=1;
L=6;
T=10;
x=linspace(0,L,100); t=linspace(0,T,100);
n=1:100;
for i=1 : length(x)
    for j=1 : length(t)
        u(i,j)=(8/(pi^2)).*sum((1./(n.^2)).*sin(n.*pi/2).*cos(n.*pi.*t(j)/6).*sin(n.*pi.*x(i)/6));
    end
end
surf(t,x,u)
xlabel('t'); ylabel('x'); zlabel('u')
title('Exercise 2.b');
 
%% Exercise 2.c
clear
clf
clc
k=1;
L=6;
T=10;
x=linspace(0,L,100); t=linspace(0,T,100);
n=1:100;
for i=1 : length(x)
    for j=1 : length(t)
        u(i,j)=(8/(pi^2)).*sum((1./(n.^2)).*sin(n.*pi/2).*cos(n.*pi.*t(j)/6).*sin(n.*pi.*x(i)/6));
    end
end
plot(x,u)
xlabel('x'); ylabel('u'); 
title('Exercise 2.c');

[darova]

c)

for i = 1:size(u,1)
    plot(t,u(i,:))
    pause(0.05)
end

[Jacob Andréasson]

thank you so much!!!!