How did the imaginary number i = root(-1) come about? Why must it exist? Can we do without it?

Yes, those of us who studied mathematics and physics after high school are familiar with the values $${i = \sqrt{-1}}$$ and ...

Is it true that "the world is made of numbers"? Tracing from Pythagoras to cosmology in a single line

The text you are reading right now, the photos saved on your smartphone, and the music you listened to yesterday are all ...