Using the cosine double-angle identity

Name: Using the cosine double-angle identity
Uploaded: 2023-10-31T23:49:08.081254081Z
Description: The cosine double angle formula tells us that cos(2θ) is always equal to cos²θ-sin²θ. For example, cos(60) is equal to cos²(30)-sin²(30). We can use this identity to rewrite expressions or solve problems. See some examples in this video.

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The cosine double angle formula tells us that cos(2θ) is always equal to cos²θ-sin²θ. For example, cos(60) is equal to cos²(30)-sin²(30). We can use this identity to rewrite expressions or solve problems. See some examples in this video. Created by Sal Khan.

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Algebra (all content)

Course: Algebra (all content) > Unit 14

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Video transcript