Write the Product as a Sum or Difference of Trigonometric $2 \sin 3 x \sin 18 x$

question 25

Multiple Choice

Write the product as a sum or difference of trigonometric functions.
- $2 \sin 3 x \sin 18 x$

• A) \(\cos 21 x + \cos 15 x\)
• B) \(\sin 21 x + \sin 15 x\)
• C) \(\cos 15 x - \cos 21 x\)
• D) \(\frac { 1 } { 2 } ( \cos 21 x + \cos 15 x )\)

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Definitions:

Class Inclusion

A cognitive ability that involves understanding that objects can belong to more than one category at the same time.

Conservation Skills

Cognitive abilities to understand that quantity, length, or number do not change when nothing is added or taken away, despite changes in form or appearance.

Centration

A cognitive limitation in preoperational stage children where they can focus on only one aspect of a situation at a time.

Reversibility

The cognitive ability to understand that actions can be reversed, restoring the original state.