An evaluation of the given integral can be based on the trig identity , which must be invoked twice during the course of the computation in Table 6.2.2(a).
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Table 6.2.2(a) Solution based on the identity
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Alternatively, the first reduction formula in Table 6.2.3, namely,
can be used with and then again with , as shown in the following computation,
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It would appear that there is less chance of making an arithmetic error in the second solution, the one based on the reduction formula. However, the two solutions are the same: the first solution can be transformed to the second by repeated application of the trig identity .