I'm struggling on this but i get the feeling it's easier than i think.

The sequence is defined by:

xn+1 = (xn + 2) / 6

where the initial value is 0.

and you need to show that

| xn+1 - xn | </= (5/6) * |xn - xn+1 | </= (1/3) * (5/6)^n-1

after having shown that 0< xn <1 (which i was able to do).

( by the way </= means 'less that or equal to", i didn't know how to put it on the computer though.)

can anyone help?