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| Conditional Trigonometric Identities |
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| In the previous sections many identities have been discussed. They are true for all values of the angles for which trigonometric functions are defined. In this section we prove identities, where a certain relationship exists among the angles considered. |
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| Many interesting and important identities are established using the relation A+B+C=180. |
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| Before we start establishing identities, it is helpful to note the following results. |
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| (i) If A + B+ C = p, then |
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