Trigonometric Identities
Trigonometric Identities
Trigonometric Identities
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Copyright © 2009 Pearson Addison-Wesley<br />
Double-Angle <strong>Identities</strong><br />
We can use the cosine sum identity to derive<br />
double-angle identities for cosine.<br />
Cosine sum identity<br />
5.5-4