Sum of roots: Vieta's Formula The roots of the equation $x^4-5x^2+2x-1=0$ are $\alpha, \beta, \gamma, \delta$. Let $S_n=\alpha^n +\beta^n+\gamma^n+\delta^n$
Show that $S_{n+4}-5S_{n+2}+2S_{n+1}-S_{n}=0$
I have no idea how to approach this. Could someone point me in the right direction?

Hint. $$ \begin {align*} S_{n+4} - 5S_{n+2} + 2S_{n+1} - S_n &= \alpha^{n+4} + \beta^{n+4} + \gamma^{n+4} + \delta^{n+4} - 5 \cdot \left( \alpha^{n+2} + \beta^{n+2} + \gamma^{n+2} + \delta^{n+2} \right) + 2 \cdot \left( \alpha^{n+1} + \beta^{n+1} + \gamma^{n+1} + \delta^{n+1} \right) - \left( \alpha^n + \beta^n + \gamma^n + \delta^n \right). \end {align*} $$Now, see what you can factor out. The coefficients should have given you this suspicion. 
