find the mean, energy and power of cosine function

i am just a matlab beginner.

x[n]=2cos(0.2*pi*n) with a length of N =100 , that is, ,0<N<99 plotted

 clear all
 n=[0:99];
 x=2*cos(0.2*pi*n);
 stem(n,x);
 legend('x[n]');
 title('Sequence of 2*cos(0.2*pi*n)');
 xlabel('n');
 ylabel('x[n]');
 axis([0 99 -2 2]);

how to use MATLAB to compute the mean, and energy and power of x[n]given mean=x, energy=Ex and power=Px.

Answer 1

[Wayne King]

You can just do:

      mean(x)
      Ex = norm(x,2)^2  % the energy 
      Px = 1/numel(x)*norm(x,2)^2 % power

If you don't want to use norm(), you just use sum()

      Ex = sum(abs(x).^2)
      Px = 1/numel(x)*sum(abs(x).^2)

Note that the RMS of the signal is

      sqrt(Px)

The Signal Processing Toolbox implements this as rms()

[Passband Modulation]

thank you very much, it works well!!

[Walter Roberson]

pinak parida commented,

power ,energy of a signal how norm works to be check?

[Abdullah Zubair]

mean(x)

Ex = norm(x,2)^2 % the energy

Px = 1/numel(x)*norm(x,2)^2 % power

what is this 2 in norm function is for?