Use an Addition or Subtraction Formula to Write $\cos 75 ^ { \circ } \cos 15 ^ { \circ } + \sin 75 ^ { \circ } \sin 15 ^ { \circ }$

question 77

Essay

Use an addition or subtraction formula to write $\cos 75 ^ { \circ } \cos 15 ^ { \circ } + \sin 75 ^ { \circ } \sin 15 ^ { \circ }$ and find its exact value.

---

Definitions:

Fight-Or-Flight

A physiological response to a perceived harmful event, attack, or threat to survival, triggering either aggression or escape.

Health Issues

Conditions or diseases affecting the health and well-being of an individual.

2011 Terrorist Attacks

Specific acts of terrorism that occurred within the year 2011, affecting various locations worldwide.

U.S. Presidential Election

A quadrennial process where citizens of the United States elect the President and Vice President of the country.