# Thread: This may be a stupid question, but...

1. ## This may be a stupid question, but...

How does (cosh squared x - sinh squared x) / (cosh squared x) equal

1 - ((sinh x / cosh x)^2)

Help appreciated!

2. Hi,

$\frac{\cosh^2x-\sinh^2x}{\cosh^2x}=\frac{\cosh^2x}{\cosh^2x}-\frac{\sinh^2x}{\cosh^2x}=1-\frac{\sinh^2x}{\cosh^2x}=1-\left(\frac{\sinh x}{\cosh x}\right)^2$

3. Thank you SO much. You're a star!