$\begin{array}{l} 2\cos \left( {5\pi - x} \right) - 3\sin \left( {\dfrac{{7\pi }}{2} + x} \right) + \cos \dfrac{{11\pi }}{2} + \cot \left( {3\pi - x} \right) + \tan \left( {\dfrac{{9\pi }}{2} - x} \right)\\ = 2\cos \left( {\pi - x} \right) - 3\sin \left( {2\pi - \dfrac{\pi }{2} + x} \right) + \cos \left( {6\pi - \dfrac{\pi }{2}} \right) + \cot \left( {2\pi + \pi - x} \right) + \tan \left( {4\pi + \dfrac{\pi }{2} - x} \right)\\ = - 2\cos x - 3\sin \left( {x - \dfrac{\pi }{2}} \right) + \cos \dfrac{{ - \pi }}{2} + \cot \left( {\pi - x} \right) + \tan \left( {\dfrac{\pi }{2} - x} \right)\\ = - 2\cos x + 3\sin \left( {\dfrac{\pi }{2} - x} \right) + \cos \dfrac{\pi }{2} - \cot x + \cot x\\ = 3\cos x - 2\cos x + \cos \dfrac{\pi }{2}\\ = \cos x \end{array}$
