$\begin{aligned}
& \left(\mathrm{e}^{\mathrm{y}}+1\right) \cos \mathrm{x} \mathrm{dx}+\mathrm{e}^{\mathrm{y}} \sin \mathrm{x} d \mathrm{y}=0 \
& \Rightarrow \mathrm{d}\left(\left(\mathrm{e}^{\mathrm{y}}+1\right) \sin \mathrm{x}\right)=0 \
& \left(\mathrm{e}^{\mathrm{y}}+1\right) \sin \mathrm{x}=\mathrm{C}
\end{aligned}$
It passes through (2π,0) ⇒c=2 Now, x=6π ⇒ey=3