Hi

I would like to prove the following inequalities,

1) , show that

2) Given that , prove that

It's in part of a book about power series expansion of functions, so I'm pretty sure they're looking for a solution involving those. I've put in the expansions for sin and cos but I don't see the logic in how to prove these statements forallx.

A nudge in the right direction would be much appreciated, thanks

Stonehambey