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## Homework Statement

Can some one please give me the proof or somewhere I can find the proof or just an explanation why

Sin(-theta) = -Sin(theta

Cos(-theta) = cos(theta)

Tan(-theta)= -Tan(theta)

Thank you..

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- Thread starter Miike012
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- #1

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Can some one please give me the proof or somewhere I can find the proof or just an explanation why

Sin(-theta) = -Sin(theta

Cos(-theta) = cos(theta)

Tan(-theta)= -Tan(theta)

Thank you..

- #2

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Once you figure out why it's true for sine and cosine, you can use the tangent's relationship with the sine and cosine to see why the third result is true.

- #3

symbolipoint

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Examine the Right-triangle values on the Unit Circle.

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