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 $\cos ^ { 2 } \frac { \pi } { 8 } - \sin ^ { 2 } \frac { \pi } { 8 }$ .

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Definitions:

Price Elasticity

Price elasticity measures the responsiveness of demand or supply of a good to changes in its price.

Absolute Value

The non-negative value of a number without regard to its sign.

Demand Function

A mathematical equation that specifies the quantity of a good or service demanded at various price levels, holding all other factors constant.

Price Elasticity

An economic metric indicating the responsiveness of the demand for a product or service to variations in its price.