How do I factor $\ t^4-2 \ $? This binomial is part of a bigger problem that I need to solve, however, I am little stuck on how to factor it. $(t-1)(t-1)(t+1)$ does not work.

$$t^4-2=\left(t^2-\sqrt 2\right)\left(t^2+\sqrt 2\right)=\left(t-\sqrt[4]{2}\right)\left(t+\sqrt[4]{2}\right)\left(t^2+\sqrt 2\right).$$
