How to change limits of y-axis? `ylim` does not work

Question

When the graph below is plotted, NSS1 which is simply a constant set equal to one is right on the top border of the graph and thus hard to see.

How can I change the length of the y-axis to say 1.2 so that the NSS1 can be seen more clearly?

lambda=5;
tau=0:30;

tau(1)=0.000001;

NSS1=1*ones(1,31);
NSS2=(1-exp(-tau/lambda))./(tau/lambda);
NSS3=((1-exp(-tau/lambda))./(tau/lambda)-exp(-tau/lambda));

%ylim([0, 1.2])
plot(tau,NSS1,'-k*',tau,NSS2,'-k+',tau,NSS3,'-ko');
xlabel('t = 0 to 30y', 'FontSize',30)
ylabel('yield','FontSize',30)

Answer 1

The reason why ylim doesn't work if you put it before the plot command is that there is no axes object it can relate to.

So there are two options:

First, you create an axes object and hold it with hold on, so the upcoming plot is plotted on the same axis.

ax = axes; hold on;
ylim([0, 1.2])

plot(tau,NSS1,'-k*',tau,NSS2,'-k+',tau,NSS3,'-ko');

or second, you plot first, the command automatically generates an axes object and you can modify its y-limits afterwards:

plot(tau,NSS1,'-k*',tau,NSS2,'-k+',tau,NSS3,'-ko');
ylim([0, 1.2])