Chapter 10, Problem 10.90E

Write $\Psi \left(x,t\right)=e^{-iEt\text{/}\hslash }\cdot \Psi \left(x\right)$ in terms of sine and cosine, using Euler’s theorem: $e^{i\theta }=\cos \theta +i\sin \theta$. What would a plot of $\Psi \left(x,t\right)$ versus time look like?