Trigonometry - Compound and Double-Angle Identities
Trigonometry - Compound and Double-Angle Identities
IP 3
Without using a calculator, show that \(\cos 108^\circ = \frac{1-\sqrt{5}}{4}\).
Solution:
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Answer:\(\cos108^\circ=\frac{1-\sqrt5}{4}\) (shown).
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