Select all the true equations. A. $\cos (15)=\sin (15)$ B. $\cos (75)=\sin (15)$ C. $\cos (75)=\cos (15)$ D. $\cos (15)=\sin (75)$ E. $\tan (15)=\tan (75)$

Step 1 ：Evaluate each equation using trigonometric functions:

Step 2 ：A. \(\cos(15) = \sin(15)\) is False

Step 3 ：B. \(\cos(75) = \sin(15)\) is True

Step 4 ：C. \(\cos(75) = \cos(15)\) is False

Step 5 ：D. \(\cos(15) = \sin(75)\) is True

Step 6 ：E. \(\tan(15) = \tan(75)\) is False

Step 7 ：\boxed{\text{Final Answer: The true equations are B and D.}}