Homework Problem 1, Due Monday February 4.
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(a) Create a vector V1 of length 120 consisting of 0,1,2,1,0,1,2,1,...

(b) Create a numeric vector V2 of length 120 consisting of the 
    values sin(2*pi^2*x) for x= 1, 2, ..., 120. 

(c) Create a character vector V3 of labels "L", "M", "H" (low, 
    medium and high) where L appears at every index where the V2 
    value is less than -0.25,  M appears at every index where the 
    V2 value falls in [-0.25, + 0.25], and H appears at every 
    index where the V2 value is greater than 0.25.

(d) Make a matrix consisting of vectors V1, V2, V3 with column 
    names "Grp","Z","Class" respectively. (Your matrix will contain
    all entries changed into character-strings.)

(e) Make a data-frame out of the same columns V1, V2, V3 as in (d),
    with the same column headings. But in this part, make sure that
    columns 1 and 2 of the resulting data-frame remain numeric, 
    while column 3 is of "character" type.