Question 1083092
Assume the problem is:

If {{{y=log(2,(x+sqrt(x^2+1)))}}}, then {{{2^y - 2^(-y)}}}
We can write {{{2^y - 2^(-y)}}} as {{{2^y - 1/2^y}}}  
the exponent equiv of logs
{{{2^y=(x+sqrt(x^2+1))}}}, therefore
:
{{{2^y - 1/2^y}}} = {{{(x+sqrt(x^2+1))}}} - {{{1/(x+sqrt(x^2+1))}}},