In this TI Nspire tutorial for the TI-Nspire CAS, the Calculator window is used to find the trigonometric identities for addition and subtraction of sine and cosine.
This is the transcript for the TI-Nspire Mini-Tutorial entitled, Trig Identities: Addi
In this TI Nspire tutorial for the TI-Nspire CAS, the Calculator window is used to find the trigo