31.1 From Analytic Geometry to an Equation We Can't Solve
Point 2 of 4
31.1.2 The Birth of the Imaginary Unit i
Core idea
Picture this: we give "the square root of negative one" a name, i; it doesn't live on the number line, but the single rule i²=−1 keeps everything else working as before
Module goal. Picking up the coordinate geometry from the last stage, we start from a genuine dead end — the real number line just isn't enough — and from there introduce the imaginary unit and the idea of complex numbers
eastmath.com · 31.1 From Analytic Geometry to an Equation We Can't Solve · 31.1.2 The Birth of the Imaginary Unit i