erorr in MATLAB programming

hello

Why does the following program give an error?

function pdex4
m=0;
x=linspace(0,0.3,50);
t=linspace(0,50);
sol=pdepe(m,@pdex4pde,@pdex4ic,@pdex4bc,x,t);
u1=sol(:,:,1);
u2=sol(:,:,2);
figure
surf(x,t,u1)
title('u1(x,t)')
xlable('Distance x')
ylable('Time t')
figure
surf(x,t,u2)
title('u2(x,t)')
xlable('Distance x')
ylable('Time t')
function [c,f,s]=pdex4pde(x,t,u,DuDx)
c=[1;0];
w=10;
v=0.9979;
a0=5;
f=[1;1].* DuDx;
F1=u(1).*((w)^2-(((v^2)/(((1+a0^2)^0.5+u(2))-(1-v^2).*(1+u(1).^2))).^0.5)/(1-v^2));
F2=-(((((v^2)/(((1+a0^2)^0.5+u(2))-(1-v^2).*(1+u(1).^2))).^0.5)).*((1+a0^2)^0.5+u(2))-1)/(1-v^2);
s=[F1,F2];
function u0=pdex4ic(x)
u0=[10;0];
function [pl,ql,pr,qr]=pdex4bc(xl,ul,xr,ur,t)
pl=[0;u1(2)];
ql=[1,0];
pr=[ur(1)-1;0];
qr=[0;1];

[KSSV]

You should specify what error you are getting to get help.

[Steven Lord]

Yes, please show the full and exact text of the error message (all the text displayed in red in the Command Window.) If there are any warning messages displayed in orange please include the full and exact text of those messages as well (indicating which are warnings and which are errors if it's not obvious.)

[m sad]

error text:

Error using pdepe (line 248)

Unexpected output of PDEFUN. For this problem PDEFUN must return three column vectors of length 2.

Error in pdex4 (line 6)

sol = pdepe(m,@pdex4pde,@pdex4ic,@pdex4bc,x,t);