How is the domain of a trigonometric function restricted so that its inverse function is defined?

Since trigonometric functions have no restrictions, there is no inverse. With that in mind, in order to have an inverse function for trigonometry, we restrict the domain of each function, so that it is one to one. A restricted domain gives an inverse function because the graph is one to one and able to pass the horizontal line test.
Answer:
do not pass the horizontal line test
Step-by-step explanation:
Trigonometric are periodic, therefore each range value is within the limitless domain values ( no breaks in between ). Since trigonometric functions have no restrictions, there is no inverse. ... A restricted domain gives an inverse function because the graph is one to one and able to pass the horizontal line test