I´ve been struggling with this problem too. Essentialiy we have to prove that the second expression in the min expression
.
is a valid
as explains magdon in
Quote:
Originally Posted by magdon
Rather than solve the inequality in (b) to get this bound, you may rather just verify that this is a bound by showing that if , then the inequality in (b) is satisfied, namely .

this means that the inequality
(1)
must be satisfied.
I have been finding upper bounds to the right hand side of (1), using the following tricks
if
(the case
must be proved apart).
,
, because
(this is not the seven in the exponent) and
.
Then we arrive at an expression that can be compared easily with the left hand side of (1) proving that this inequality is valid.