(Proofs of any of the individual steps are available upon request, should you find yourself thinking that I’m pulling a 1=0 trick.) So then
This converges very slowly, though, because for every two steps forward you take
a step back. (More precisely: for every 1 step forward, you take steps back.) You can make it converge faster by combining the forward step and the smaller backward step into a single, smaller, forward step:
whence