# How do you use the half-angle identity to find the exact value of cos(-pi/12)?

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To find the exact value of (\cos\left(-\frac{\pi}{12}\right)) using the half-angle identity, follow these steps:

- Start with the half-angle identity for cosine: (\cos\left(\frac{\theta}{2}\right) = \sqrt{\frac{1+\cos(\theta)}{2}}).
- Substitute (\theta = -\frac{\pi}{6}) into the identity.
- Calculate (\cos\left(-\frac{\pi}{6}\right)) using known values (or the unit circle).
- Plug the value of (\cos\left(-\frac{\pi}{6}\right)) into the half-angle identity.
- Simplify the expression to find the exact value of (\cos\left(-\frac{\pi}{12}\right)).

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When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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