I have another post about sequences but this question seems easier (hence why I posted it here!).

However, "easier" is used relative to the other question I am stuck on (posted in Advanced Algebra).

The problem is:

All the equations I have tried have failed. I can't think of a method to do this question properly =(Think of an example to show that the statement,

if then

is false, even if for all n

Any ideas would be greatly appreciated!