The iteration step in order to solve for the cube roots of a given number N using the Newton-Raphson’s method is
- $x_{k+1}=x_k+\frac{1}{3}(N-x^3_k)$
- $x_{k+1}=\frac{1}{3}(2x_k+\frac{N}{x^2_k})$
- $x_{k+1}=x_k-\frac{1}{3}(N-x^3_k)$
- $x_{k+1}=\frac{1}{3}(2x_k-\frac{N}{x^2_k})$