If a trigonometric function has an inverse function,

Inverse trigonometric function is the inverse function of trigonometric function;

Inverse trigonometric function is the inverse function of trigonometric function with inverse function.

What is its mathematical significance,

Its mathematical significance is:

The angle of the value defined in the domain within the principal value interval.

such as

The arcsine represents the angle on [-π/2, π/2], and the domain is [- 1,1];

The arccosine represents the angle on [0, π], and the domain is [- 1,1];

Arctangent represents the angle on (-π/2, π/2), and its domain is R.

What's the role?

It is influenced by its mathematical meaning-representing the corresponding angle,

Especially the non-special angle corresponding to the non-special value in the principal value interval,

Then find out all the angles that meet the conditions through inductive formulas.

This is often used in solving trigonometric equations. .....