Question: what is the inverse function of square?
Answer: Example: Square and Square Root (continued) of each other about the diagonal y=x. Note: when we restrict the domain to x ≤ 0 (less than or equal to 0) the inverse is then f-1(x) = −√x: {x2 | x ≤ 0 } {−√x | x ≥ 0 }