Trig Identities: Addition and Subtraction Identities for Sine and Cosine

Open a new calculator window.

Use the tExpand() command from the algebra menu as shown.

Input the expression "sine of a + b" within the tExpand function.

Press Enter.

Repeat with the three other trigonometric identities.

You can cut and paste these identities into a word processing program

to create a table that lists these identities.