# Help with Simplification

## Homework Statement

Hey, does anyone know how to further simplify this:

## Homework Equations

ln(exp(-a) + exp(a))?

## The Attempt at a Solution

rock.freak667
Homework Helper

There is no such rule as ln(x+y)=lx+lny if that is what you wanted to know. The most I can think of is that cosh(x)= 1/2(ex+e-x)

Thank you, this is good. I was after a trig simplification.
I knew one for 2cos(x) = exp(-ix) + exp(ix) but couldn't remember one without the imaginary.
Ta!!!