The function A = s^2 giving the area of a square as a function of its side length

Linear or Nonlinear:

Domain:

The function A = s^2 is a nonlinear function because it has a variable (s) raised to the power of 2, which makes it a quadratic function.

The domain of this function is all real numbers because the side length (s) of a square can be any positive or negative real number.

Increasing or Decreasing:

The function A = s^2 is increasing. As the side length (s) of the square increases, the area (A) also increases. Similarly, as the side length decreases, the area decreases. So, the function is monotonically increasing.