How to write a legend in latex format

Npc=2;

legend('\Sigma_{i=1}^{Npc} x^\prime_i','Total L_w','Noise');

In the below figure's legend, how do we need to include a variable Npc.

Answer 1

[Star Strider]

Try this:

Npc=2;
legend(sprintf('\\Sigma_{i=1}^{%d} x^\\prime_i',Npc),'Total L_w','Noise');

That worked correctly when I tested it with a plot of random data.

Answer 2

[darova]

Concatenation?

Npc=2;
legend1 = ['\Sigma_{i=1}^{', num2str(Npc) ,'Npc} x^\prime_i'];
legend(legend1,'Total L_w','Noise');