f := x -> x sin(2.2 x) - 5 sin(x)

                                    x sin(2.2 x) - 5 sin(x)
            NMf := x -> x - ----------------------------------------
                            sin(2.2 x) + 2.2 x cos(2.2 x) - 5 cos(x)

18.000000000000000000
19.368113045219229254
26.353190409602634801
23.502860797695800507
19.960984068175941358
20.101628877680130895
20.100303814440213602
20.100304112490147440
20.100304112490162322 <<< 8th iteration - not the closest root
20.100304112490162322