12. Trigonometric Functions

Use the even-odd identities to evaluate the expression.

$\cos\left(-\theta\right)-\cos\theta$

Use the even-odd identities to evaluate the expression.

$-\cot\left(\theta\right)\cdot\sin\left(-\theta\right)$

Select the expression with the same value as the given expression.

$\sec\left(-\frac{4\pi}{5}\right)$

Select the expression with the same value as the given expression.

$\sin\left(-38\degree\right)$