# Hyperbolic definitions

• Nov 25th 2012, 09:32 AM
minicooper58
Hyperbolic definitions
Hi , I'm stuck on part b) of the attached proving cosh(x-ln2)=sinh(x) .
Substituting and simplifying seems to give me e^(x)-e^(-x) and not with the half to prove the identity .
• Nov 25th 2012, 09:59 AM
Plato
Re: Hyperbolic definitions
Quote:

Originally Posted by minicooper58
Hi , I'm stuck on part b) of the attached proving cosh(x-ln2)=sinh(x) .
Substituting and simplifying seems to give me e^(x)-e^(-x) and not with the half to prove the identity .

I really do not follow what is going on in that attachment.

By here are two facts.

$e^{x-\ln(2)}=\frac{e^x}{2}$ so $\cosh(x-\ln(2))=\frac{e^{2x}+4}{4e^x}$