`sin (2x + 1) = cos (3x + 2)`
`<=> sin (2x + 1) = sin (π/2 - 3x - 2)`
`<=>` \(\left[ \begin{array}{l}2x + 1 = \dfrac{π}{2} - 3x - 2 + k2π\\2x + 1 = π - \dfrac{π}{2} + 3x + 2 + k2π\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}5x = \dfrac{π}{2} - 3 + k2π\\-x = \dfrac{π}{2} + 1 + k2π\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x = \dfrac{π}{10} - \dfrac{3}{5} + k\dfrac{2π}{5}\\x = -\dfrac{π}{2} - 1 + k2π\end{array} \right.\) `(k ∈ ZZ)`
