Colleen and Jolleen both use their calculators to determine $\text{sin}\left(30^\circ\right)$. Colleen gets $\text{sin}\left(30^\circ\right) = –0.9880316241$, but Jolleen gets $\text{sin}\left(30^\circ\right) = 0.5$. Is one of their calculators broken, or is something else going on? Why do they get different answers?