Find the Exact Value by Using a Half-Angle Identity $\cos 165 ^ { \circ }$

question 276

Multiple Choice

Find the exact value by using a half-angle identity.
- $\cos 165 ^ { \circ }$

• A) \(\frac { 1 } { 2 } \sqrt { 2 - \sqrt { 3 } }\)
• B) \(- \frac { 1 } { 2 } \sqrt { 2 - \sqrt { 3 } }\)
• C) \(- \frac { 1 } { 2 } \sqrt { 2 + \sqrt { 3 } }\)
• D) \(\frac { 1 } { 2 } \sqrt { 2 + \sqrt { 3 } }\)

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Definitions:

Categorical Variables

Non-numeric variables that represent categories or groups.

Pie Charts

A type of graph in which a circle is divided into sectors that each represent a proportion of the whole, often used to visualize the relative proportions of different categories.

Bar Graphs

A visual representation of data using bars of varying heights or lengths to show the values of different categories.

Leaf

In botany, this refers to the flat, thin plant organ specialized for photosynthesis; in data visualization, particularly in a "tree" structure, it represents an endpoint or a data point that does not branch out further.