Yes, I completed question number 1.
The letter A is not periodic and B is!
Your approximate period by the graph that MatLab gave me is something around 0.7.
I can solve 1a and 1b, but I could not figure out if a function is periodic or not.
Both were like this ...
a)
t = (-10:0.01:10);
x1 = t>=3;
x2 = t<1;
xtot=x1+x2;
plot(t,xtot)
axis ([-10,10,0,1.2])
b)
t = (-0.5:0.001:0.5)';
x1 = 10*cos(100*t);
x2 = 2*sin(100*t);
xtot=x1-x2;
plot(t,xtot)
axis...