Problem with plotting functions

Hey! I have been working ith this exersice for a long time and it is the first time i work with plotting this type of functions. Could someone please help with how to do this?

I need espacially help with b and c

[Stephen23]

What have you tried so far?

(Please write comments as comments. The answers are for answering the question).

[Jacob Andréasson]

I need espacially help with b and c on question 2

[Jacob Andréasson]

x=0:0.1:6;

t=0:0.1:10;

syms n

F1=symsum((1/(n^2))*sin(n*pi/2)*cos(n*pi*t/6)*sin(n*pi*x/6),n,0,Inf)

u=(8/(pi^2))*F1;

plot3d(x,t,u)