Write the Sum as a Product $\cos 4 x + \cos 5 x$

question 84

Essay

Write the sum as a product. $\cos 4 x + \cos 5 x$

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Definitions:

Fossil Fuels

Non-renewable energy sources formed from the remains of plants and animals over millions of years, such as coal, oil, and natural gas.

Future

A period of time that has not yet happened, but can be planned or predicted based on current knowledge and trends.

United Nations Report

A document published by the United Nations that covers a wide range of global issues, from human rights to environmental concerns.

Our Common Future

A report by the World Commission on Environment and Development that introduced the concept of sustainable development.