# Thread: Hyperbolic Functions Identity Help

1. ## Hyperbolic Functions Identity Help

I have to prove this identity and I'm having difficulties.
I attempted changing the things into sinh and cosh and into their respective definitions, but I ended up getting 2e^x / 0

Any suggestions on how to try this. My teacher dropped this on me and it's due tomorrow.

2. Originally Posted by DemonGal711
I have to prove this identity and I'm having difficulties.
I attempted changing the things into sinh and cosh and into their respective definitions, but I ended up getting 2e^x / 0

Any suggestions on how to try this. My teacher dropped this on me and it's due tomorrow.
$\mathrm{sinh}(x)=\frac{\mathrm{e}^{x}-\mathrm{e}^{-x}}{2}$
$\mathrm{cosh}(x)=\frac{\mathrm{e}^{x}+\mathrm{e}^{-x}}{2}$
$\mathrm{tanh}(x)=\frac{\mathrm{sinh}(x)}{\mathrm{c osh}(x)}$
............ $=\frac{\mathrm{e}^{x}-\mathrm{e}^{-x}}{\mathrm{e}^{x}+\mathrm{e}^{-x}}$
............ $=\frac{\mathrm{e}^{2x}-1}{\mathrm{e}^{2x}+1}$
it must not be hard to prove what you want by using these identities.

also visit: Hyperbolic function - Wikipedia, the free encyclopedia

3. Thank you. My teacher never gave us the last expression for how to write tanh(x) so I was trying to do it with what he had given us. I think I would have been there forever.