Use an Identity to Write the Expression as a Single $2 \cos ^ { 2 } 22.5 ^ { \circ } - 1$

question 259

Multiple Choice

Use an identity to write the expression as a single trigonometric function or as a single number.
- $2 \cos ^ { 2 } 22.5 ^ { \circ } - 1$

• A) \(\frac { \sqrt { 2 } } { 4 }\)
• B) \(\frac { \sqrt { 3 } } { 3 }\)
• C) \(\sqrt { 3 }\)
• D) \(\frac { \sqrt { 2 } } { 2 }\)

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Definitions:

Prefix

A group of letters added at the beginning of a word to modify its meaning, such as 'un-' in 'unhappy'.

Combining Form

In linguistics and anatomy, a form that combines with another form to create a new word or term, often used in medical terminology.

Suffix

A morpheme added at the end of a word to alter its meaning or create a new word.

Root

The part of a plant that attaches it to the ground and absorbs nutrients and water from the soil.