The range of all values of $\text{'}\theta \text{'}$such that $\sin 3\theta -\cos 3\theta >0$

$$\begin{gathered} We have \sin 3\theta -\cos 3\theta >0 \\ \Rightarrow \frac{1}{\sqrt{2}}\sin 3\theta -\frac{1}{\sqrt{2}}\cos 3\theta >0 \\ \Rightarrow \sin \left(3\theta -\frac{\mathrm{\pi }}{4}\right)>0 \\ \Rightarrow 0<3\theta -\frac{\mathrm{\pi }}{4}<\mathrm{\pi } \\ \Rightarrow \frac{\mathrm{\pi }}{4}<3\mathrm{\theta }<\frac{5\mathrm{\pi }}{4} \\ \Rightarrow \frac{\mathrm{\pi }}{12}<\mathrm{\theta }<\frac{5\mathrm{\pi }}{12} \\ \Rightarrow 2\mathrm{n\pi }+\frac{\mathrm{\pi }}{12}<\mathrm{\theta }<2\mathrm{n\pi }+\frac{5\mathrm{\pi }}{12}, n\in I \end{gathered}$$