Hi @mmcky

The lecture

https://intro.quantecon.org/complex_and_trig.html

appears to have a strange output

It might be due to the latex engine in the intro series.

From documentation:

https://docs.sympy.org/latest/tutorials/intro-tutorial/printing.html

If Latex is not installed, but Matplotlib is installed, it will use the Matplotlib rendering engine. If Matplotlib is not installed, it uses the Unicode pretty printer.