deriving finite difference scheme for partial differential equation.

[shelly89]

Hi, Can anyone help with the last part of this question, I just cannot seem to derive the scheme!

\(\displaystyle \frac{u_{j}^{n+1}- u_{j}^{n-1}}{ 2 \Delta t} - 5 \frac{u_{j+1}^{n} - u_{j-1}^{n}}{ 2 \Delta x } = 0 \)