Real World Applications

Architecture: These trigonometric identities can be used to proportionally design anything, from cars, to tables, all the way up to bridges and buildings. With these identities you can accurately measure the dimesions of anything you design. For example:

Audio & Light: Trigonometry is essential when it comes to music, as well as the construction of things such as sirens, Lights, and more. All of these things have to do with waves, which would require extensive knowledge with sin and cosine waves. Being able to make songs, sirens, lights and more requires an ability to use these identities and prior trigonometry skills.

Engineering: In engineering fields, math and physics are a must in order to complete designs and create items. In order to do many things, engineering requires the use of trigonometric identities. For example, when creating a boat, car, or plane, engineers must take into account vibrations from the engines of the vehicles, as well as how air flows around it. In order to do this, they may need to use Trigonometric identities to correctly build these vehicles, as well as whatever else they make, to make them more efficient, cost effective, safe, etc.

SOURCES

Beach, Emily. "What Are Some Real-Life Applications of Trigonometry?" Sciencing, 13 Mar, 2018, sciencing.com/real-life-applications-trigonometry-7769833.html.