Trig identities are trigonometry equations that are always true, and they're often used to solve trigonometry and geometry problems and understand various mathematical properties. Knowing key trig identities helps you remember and understand important mathematical principles and solve numerous math problems.

Where are trig identities used in the real life?

Trigonometry can be used to roof a house, to make the roof inclined ( in the case of single individual bungalows) and the height of the roof in buildings etc. It is used naval and aviation industries. It is used in cartography (creation of maps).

Are trig identities used in calculus?

What are trigonometric identities doing on a Calculus exam? ... Trigonometry is useful when setting up problems involving right triangles. Moreover, the trigonometric identities also help when working out limits, derivatives and integrals of trig functions.