Use a Double-Angle Formula or Half-Angle Formula to Simplify $\cos ^ { 2 } \frac { \pi } { 8 } - \sin ^ { 2 } \frac { \pi } { 8 }$

question 114

Essay

Use a double-angle formula or half-angle formula to simplify $\cos ^ { 2 } \frac { \pi } { 8 } - \sin ^ { 2 } \frac { \pi } { 8 }$ .

---

Definitions:

Subsidy

A form of financial aid or support extended to an economic sector, typically by the government, to promote beneficial economic activities.

Deadweight Loss

The lost economic efficiency when the equitable or allocatively efficient outcome is not achieved, often due to taxes, subsidies, or monopolies.

Excise Tax

A tax imposed on specific goods, services, or activities, usually to discourage their use or to raise revenue.

Elasticities

Measurements of how changing one economic variable affects others, such as how quantity demanded will change as a result of price changes.