Show by means of suitable sketch graphs that the equation
$$( x - 2 ) ^ { 4 } = x + 16$$
has exactly 2 real roots.
State the value of the smaller root.
Use the iterative formula
$$x _ { n + 1 } = 2 + \sqrt [ 4 ] { x _ { n } + 16 }$$
with a suitable starting value, to find the larger root correct to 3 decimal places.