Step 1: Understand what a trigonometric identity is. A trigonometric identity is an equation that is true for all values of the variable where both sides are defined.
Step 2: Look at the options provided in the question. Identify if each option is a true statement for all values of the variable.
Step 3: Check each option one by one. If an option holds true for all values, it is a trigonometric identity.
Step 4: Conclude that since all the given options are true for all values, they are all identities.
