Julia Sets and the Mandelbrot Set

Complex Newton's Method

Derivation of the Newton's Method Formula

We derive the relation between x1 and x0; the others are similar. Note the points (x0, f(x0)) and (x1, 0) lie on the line tangent to the graph of y = f(x) at the point (x0, f(x0)). The slope of the tangent line is f '(x0), so we have

f '(x0) = (f(x0) - 0) / (x0 - x1)

Solving this for x1 gives

x1 = x0 - f(x0)/f '(x0)

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