(d) The given expression can be written as $\frac{1 + \cos{y - \sin^{2}y}}{1 + \cos y} + \frac{\left( 1 - \cos^{2}y \right) - \sin^{2}y}{\sin{y(1 - \cos y)}}$ $= \ \frac{\cos{y\ \left( 1 + \cos y \right)}}{1 + \cos y} + 0 = \cos y$
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