Tom K. answered 05/22/20
Knowledgeable and Friendly Math and Statistics Tutor
The easiest way to disprove this is with a counterexample. Consider f(x) = x * sqrt(1-x)
f'(x) = sqrt(1-x) - x/(2(sqrt(1-x)))
Roots are at 0 and 1.
Start at .6, which is closer to 1.
xn+1 = xn - f(xn)/f'(xn)
We converge to the solution at 0