i'm trying to plot this code , with t,x,l variables ...

i'm getting this error "Error using ./ 
Matrix dimensions must agree.

Error in Uentitled5 (line 16)
a=cos(Lambda1.\*(x./L));"

```
t=1:0.5:300;
x=0:0.1:100;
L=0:0.3:100;
Bi=0.01;
A1=1.0017
Lambda1=0.0998
a=cos(Lambda1.*(x./L));
theta=(A1.*exp(-(Lambda1.^2).*t).*a);
for i=t
    plot(t,theta,'-') 
    for j=x
        plot (x,theta,'-','green')
    end
    for k=L
        plot (L,theta,'-','red')
    end
end
title('Dimensionless Temperature for Plane Wall  ')
xlim([0 2])
ylim([0 350])
xlabel('\Theta(0)')
ylabel('t(Time in Seconds)')

```