Use the Product-To-Sum Formulas to Rewrite the Product as a Sum

question 30

Multiple Choice

Use the product-to-sum formulas to rewrite the product as a sum or difference.​ $$10 \cos 45 ^ { \circ } \cos 20 ^ { \circ }$$ ​

• A)​ \(10 \left( \cos 25 ^ { \circ } + \cos 65 ^ { \circ } \right)\)
• B)​ \(\cos 25 ^ { \circ } + \cos 65 ^ { \circ }\)
• C)​ \(5 \left( \cos 65 ^ { \circ } - \cos 25 ^ { \circ } \right)\)
• D) \(5 \left( \cos 25 ^ { \circ } + \cos 65 ^ { \circ } \right)\)
• E)​ \(5 \left( \cos 65 ^ { \circ } + \sin 25 ^ { \circ } \right)\)

---

Definitions:

Marginal Utility

The incremental pleasure or benefit a person achieves by consuming an additional unit of a good or service.

Total Utility

The total satisfaction or benefit a consumer derives from consuming a particular quantity of goods or services.

Utility Schedule

A table showing the different levels of satisfaction or utility that a consumer derives from consuming different amounts of a good or service.

Worth

The value or importance of something, often measured in terms of money or utility.