Explain in your own words what trigonometric identities are

Explain in your own words what trigonometric identities are and why we need them.

Solution

Trigonometric identities are equalities that hold true for each and every possible value value of angle.

By using trigonometric identities, we can boil down complex trigonometric problem into simpler and manageable form.

Eg:

1. Ratio identities

2. Pythagorean trigonometric identities

3. Double angle and half angle identities

Etc.