Exercise 1 and 2
"[...] however it confuses me the way the question is written!" Agree; the very same vector has three different names, x, vec and v. (It might be about level of abstraction; an effort to distiguish between the vector and its representation in Matlab.)
The text is ok.
There are relevant examples in the documentation on plot()
doesn't follow the instruction. The last sentence says
function f = density( x, m , s )
(to my best understanding)