This is LaTeX code:
[latex]
t^4+1=\left(t-\frac{\sqrt{2}}{2}-\frac{\sqrt{2}}{2}i\right)\left(t-\frac{\sqrt{2}}{2}+\frac{\sqrt{2}}{2}i\right)\left(t+\frac{\sqrt{2}}{2}-\frac{\sqrt{2}}{2}i\right)\left(t+\frac{\sqrt{2}}{2}+\frac{\sqrt{2}}{2}i\right)
[/latex]