Note that I'm trying to study complex numbers online (Can't find much good stuff..). So if I'm correct to solve a function like this $f(x) = x^2+1$ we need a 4D graph. Or 2 2D graphs basically. A x-axis,x-imaginary-axis and a y-axis,y-imaginary-axis. My question is. "Why?!" Can't we just integrate those 2 imaginary axis as one like with the classical xyz system with z = imaginary axis. Then couldn't we work in the 3D space between those 2 planes?