I just did a question where I had $sinh^2(x)$
I know this is simply $(sinh(x))^2$ however couldn't work out where the extra 2 came from when working out.
$sinh(x) = \frac{e^x-e^{-x}}{2}$
so
$sinh^2(x) = (\frac{e^x-e^{-x}}{2})^2$
which I figured
= $\frac{e^xe^x-e^{-x}e^{-x}}{4}$
= $\frac{e^{2x}-e^{-2x}}{4}$
However I am told the answer
= $\frac{e^{2x}-2+e^{-2x}}{4}$
And I don't know where the 2 came from