Question 455832
{{{y = 3sec(expr(1/4)x)}}}

We find the length of a period by dividing 
{{{2pi}}} by {{{1/4}}}

{{{2pi/(1/4)=2pi*expr(4/1)=8pi}}}

So we want to draw the graph from 0 to {{{8pi}}}

Divide {{{8pi}}} by 4 to get {{{2pi}}} so we mark
the graph off in units of {{{2pi}}} 

{{{drawing(600,700,-1,8pi+1,-20,20,

graph(600,700,-1,8pi+1,-20,20,3/cos(.25x) ),
green(line(2pi,-21,2pi,21),line(6pi,-21,6pi,21)),
locate(2pi-.5,1,2pi),locate(4pi-.5,1,4pi),locate(6pi-.5,1,6pi),
locate(8pi-.5,1,8pi)

 )}}}

Edwin</pre>