You aren't plotting a function, but a vector. Replace fplot by plot, or replace your input by a function. Actually, doing both will teach you a valuable lesson about aliasing.
It is always a good idea to read the documentation carefully when you are getting unexpected results or errors.
Here is a code example of both options (using subplot to show them in one figure):
clc
%clear %no need to use clear
disp(' Question Number 2')
x=0:1:10;
f=@(x) 40./(1+((x-4).^2) + 5*sin((20*x)/pi));
y=f(x);
figure(1),clf(1)%only use clf in debugging
subplot(1,2,1)
plot(x,y)
ylim([-35 35])%ensure same view for both plots
subplot(1,2,2)
fplot(f,[min(x) max(x)])
ylim([-35 35])%ensure same view for both plots
