EasyAlgorithms & Numerical

Newton’s Method for √2

Goldman SachsJane Street

Newton’s iteration for √2 is xn+1=12(xn+2xn)x_{n+1} = \tfrac12\left(x_n + \tfrac{2}{x_n}\right). Starting from x0=2x_0 = 2, what is x1x_1?

Approach

Plug x0=2x_0 = 2 into the iteration.

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