The domain (input values) of the sine function is: O A. angle measures between 0 and 7 radians.
O B. angle measures less than 90°.
C. all angle measures, including negative angles.
O D. angle measures between 0 and 21 radians.

The input of each of these functions is always an angle, and as you learned in the previous sections, these angles can take on any real number value. Therefore the sine and cosine function have the same domain, the set of all real numbers, \begin{align*}R\end{align*}