Which of the Following Statements Are Identities?
A) $\sin \theta=\cos \theta$

Multiple Choice

Which of the following statements are identities?

A) $\sin \theta=\cos \theta$
B) $\sin (x) =\sin (x+4 \pi)$
C) $\sin ^{2} t+\cos ^{2} t=1$
D) $\cos (2 \theta) =2 \cos \theta \sin \theta$
E) $\csc x=\frac{1}{\sin x}$
F) $\cos \theta=\frac{\sqrt{3}}{2}$