Question
In Exercises $93-110$ , verify the identity algebraically. Use a graphing utility to check your result graphically. $$\cos 3 \beta=\cos ^{3} \beta-3 \sin ^{2} \beta \cos \beta$$
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We can rewrite this as $\cos 2x = 2\cos^2x - 1$ by using the Pythagorean identity $\sin^2x + \cos^2x = 1$. Show more…
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