Mean and effective value of a function over one period

How to compute mean and effective value of a function s(t)=2cos(2pi*f*t) for f=5Hz over one period, with discretization step 0.001?

Code for plotting discrete function:

t=0:.001:.25; %random interval
x=2*cos(2*pi*5*t);
stem(x);

Answer 1

[Star Strider]

The ‘mean’ value is just that:

mean_x = mean(x);

I don’t know what you intend by ‘effective value’. If you mean RMS, it’s the square root of the mean of the squared value of the signal:

RMS_x = sqrt(mean(x.^2));

[Randy Marsh]

mean_x = mean(x);

doesn't seem to work with functions, only with arrays. Could you show the working code?

[Star Strider]

Both work with the data you posted.

I don’t understand ‘doesn’t seem to work with functions’. What do you want it to work with? What are you doing?

[Randy Marsh]

This code doesn't compute mean value and effective value (magnitude):

t=0:.001:.25; %random interval
x=2*cos(2*pi*5*t);
stem(x);
mean_x=mean(x);
RMS_x = sqrt(mean(x.^2));
dsp(mean_x);
dsp(RMS_x);

Could you point out why this doesn't work?

[Star Strider]

I don’t have the DSP System Toolbox, so if it’s necessary to use it to find out what’s wrong, I can’t.