The iteration formula to find the square root of a positive real number $b$ using the Newton Raphson method is
$x_{k+1} = 3(x_k+b)/2x_k$
$x_{k+1} = (x_{k}^2+b)/2x_k$
$x_{k+1} = x_k-2x_k/\left(x^2_k+b\right)$
None of the above
take x= root b
x^{2}=b
f(x)=x^{2}-b
x_{n+1} = (x^{2}+b) / 2x