(a) $\int_{}^{}{(1 - \cos{x)\ cosec^{2}dx}} = \int_{}^{}\frac{1 - \cos x}{1 - \cos^{2}x}\ dx$ $= \int_{}^{}\frac{1}{1 + \cos x}\ dx$ $= \frac{1}{2}\ \int_{}^{}{\sec^{2}\frac{x}{2}}\ dx = \tan\frac{x}{2} + c$
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