@Buey Cande See the following changes to your code
Fao=1.5;
%ep=0;
d=[0.1:0.25:1];
kprime=3.*(3./(60.*d).^2).*(((60.*d).*coth(60.*d.*pi./180))-1);
alpha0=0.8*10^-4./d;
Cao=0.567;
y0=[0 1];
Wspan=[0 5];
figure(1)
hold on
for k = 1:numel(kprime)
[W,y] = ode45(@(W,y) DEs(Cao,Fao,kprime(k),alpha0(k),W,y),Wspan,y0);
plot(W, y,'linewidth',2)
end
function dey = DEs(Cao,Fao,kprime,alpha0,W,y)
dey = zeros(2,1);
dey(1) = ((Cao.*(1-y(1)).*y(2)).^2)/Fao.*kprime;
dey(2) = (-alpha0./(2.*y(2)));
end
axis([0 5 0 0.95])
grid
%legend('x(W)', 'y(W))
