I'd like to plot the graph in polar coordinates of the function r=f(t)=2/cos(t), which should be a vertical line parallel to the y-axis. I've tried it with two different commands, and below you can see the results
plot(2/cos(theta), coords = polar)

What is going on here?
I then tried using polarplot from the plots package.
with(plots):
polarplot(2/cos(t), t = 0 .. 2*Pi)

Shouldn't the graph be a vertical line at 2?
Notice that if I plot two similar plots
polarplot([1/cos(t), 2/cos(t)], t = 0 .. 2*Pi)
The same result is obtained

What is going on here?