Real-valued secant function over the complex plane
The restricted domain is the set of complex numbers z for which sec(z) is real-valued. These are complex numbers on the real axis (x-axis), and complex numbers whose real part is a multiple of pi. The graph of a hyperbolic secant lies above or below complex numbers of the form n*pi+y*i where n is an integer. The 2D window shows the restricted domain. The 3D window can be manipulated to view the graphs.
Dr. John Gresham
Tarleton State University