(1)  To sketch the plot, go to web-site www.desmos.com/calculator

     Find there free of charge plotting tool for common use.

     Print the equation of the function and get the plot in the next instance.



(2)  In this problem, there are 2 (two) stretching factors: one vertical and one horizontal, 
     and both deserves to be discussed.

     Vertical stretching factor is 5.  It is the coefficient (multiplier) before the function "sec".

     In this problem, this coefficient is greater than 1, so it really produces vertical stretching 
     with coefficient 5.


     Horizontal stretching coefficient is 1/3, and because it is less than 1, in this problem 
     it is better to speak about horizontal compression with coefficient 3.

     The period is  .


(3)  Since  5sec(3x) = , vertical asymptotes are where cos(3x) is zero.

     cos(3x) is zero where 3x = ,  or  at  x= ,  k= 0, +/-1, +/-2, . . . 

     So, vertical asymptotes are at x= ,  k= 0, +/-1, +/-2, . . . 

     First two vertical asymptotes in positive domain are at x=   and  x= .