Averaging two curves of a graph

For my project I need to find and plot the average of the curves produced by this code, then take their logarithm and plot that. I've tried to use previous answers however I'm completely new to MATLAB and have been struggling a lot, so I was wondering if anyone could please help out?

clear;

t_end=30;                         % time
a12=0.4;                   % level of toxicity
a21=0.6;
ht=0.1;        % time step size
%inital conditions:
u=0.1;
v=0.5;
nh=t_end/ht;

%--------------------------------------------
t=0; k=0;
U1=zeros(nh,1);
V1=zeros(nh,1);
for j= 1:nh
 U1(j)=u;
 V1(j)=v;
 u0=u+ht*u*(1-u-a12*v);   
 v0=v+ht*v*(1-v-a21*u);
 u=u0;
 v=v0;
 t=t+ht;
 k=k+1;
 end;
% Defining the time
   E=0:ht:t;
  % plotting the profiles

figure
 plot(E(2:end),U1,'b',E(2:end),V1,'r');
xlabel('Time') 
ylabel('Relative Populations') 
legend({'= u','= v'},'Location','southeast')
% Equations to quantify the success of invasions.  

[dpb]

So, why can't you use mean([U1 V1],2)?

Altho it would be easier to not use two variables but an array with two columns...

[Alex Totir]

Thank you very much!