Displaying two different variable legends in the same figure

I am trying to display two legends in the same figure.Here, z1,z2 and z3 all are variables.Please suggest.
Suppose z1=0.4, z2=0.9, & z3=0.25
  lgd1=legend(['r_th=' num2str(z1)]);
  lgd2=legend(['K=' num2str(z2+z3)]);

[jonas]

Do you need multiple legends or can you instead use one legend with multiple rows?

[Dharma]

Thanks. I am trying to get display like this:
r_th=0.4, K=0.9+0.25=1.15. 
It can be in same row or multiple rows.

[jonas]

You still did not answer my question though. Yuvaraj's answer shows you how to manipulate the plot by superimposing two axes with one legend on each axes, which is a way to make 2 legends. I believe what you are really after is a single legend with multiple inputs, which is really basic. See the documentation for the correct legend syntax.

Answer 1

[Yuvaraj Venkataswamy]

 hAx(1) = axes();

hLine(1) = plot(1:10, 'Parent',hAx(1));

set(hAx(1), 'Box','off')

legend(hLine(1), 'line')

hAx(2) = copyobj(hAx(1),gcf);

delete( get(hAx(2),'Children') ) hLine(2) = plot(sin(1:10), 'Color','r', 'Parent',hAx(2));

set(hAx(2), 'Color','none', 'XTick',[], ... 'YAxisLocation','right', 'Box','off') %# make it transparent legend(hLine(2), {'curve'}, 'Location','NorthWest', 'Color','w')

Answer 2

[Star Strider]

You can only plot one legend in each axes object.

With that restriction, you can plot them as 1 row and 2 columns, (or 2 columns and 1 row in R2018a and later):

legend({sprintf('r_{th} = %.2f',z1), sprintf('K = %.2f + %.2f = %.2f', z2, z3, z2+z3)}, 'Location','N')                   % One Column, Two Rows
legend({sprintf('r_{th} = %.2f',z1), sprintf('K = %.2f + %.2f = %.2f', z2, z3, z2+z3)}, 'Location','N', 'NumColumns',2)   % Two Columns, One Row (R2018a+)

[Dharma]

Both r_th and K are initial parameters (not axes parameter) and I 
define their value at the beginning of code. For example:
z1=0.4; z2=0.9; z3=0.2;
r_th=z1;
K=z2+z3;
What I am trying to do is I want to choose their different value 
randomly (at the beginning of code) without changing their value also in 
legend every time. Please suggest.

[Star Strider]

I have nothing to suggest. I have no idea what you want.