What is the domain of $\sin^{-1} x + \tan^{-1} x$?

Explanation

1. 01

   Each inverse function must get an input from its domain: $\sin^{-1} x$ needs $-1 \le x \le 1$; $\tan^{-1} x$ needs nothing.

2. 02

   So the sum is defined where both are: $-1 \le x \le 1$.