Answer
(a) see graph. Subtract $e^{-x}$ from $e^x$ to obtain $e^x-e^{-x}$, then shrink the curve by a factor of 2 to get $sinh(x)$
(b) $sinh(-x)=\frac{e^{-x}-e^{-(-x)}}{2}=\frac{e^{-x}-e^{x}}{2}=-\frac{e^{x}-e^{-x}}{2}=-sinh(x)$ end prove.
Work Step by Step
see above.