How can i generate 100 samples and plot it from a given function? and then the absolute value?

Consider an envelope detector that would be used to detect the message sent in an AM system. Consider the envelope detector as a system composed of the cascading of two systems: one which computes the absolute value of the input, and a second one that low-pass filters its input. A circuit that is used as an envelope detector consists of a diode circuit that does the absolute value operation, and an RC circuit that does the low-pass filtering. The following is an implementation of these operations in the discrete-time system. (Use Matlab)

[Walter Roberson]

I am not clear what the tag "oman" has to do with this topic?

http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags

[Walter Roberson]

You are given a function, but what parameters does it have? How do you generate even one value from it? Is it a probability distribution as a formula rather than being a function?