What is the difference between a linear interval and a nonlinear interval on a graph? How would they look?

Answer with explanation:

In linear interval the graph is continuously increasing or Continuously decreasing. That is, it will be a straight line. It can be either increasing function or decreasing function.

While in Non linear interval, the graph of function may be increasing in certain interval that is period and decreasing in other. It can't be said either increasing function or decreasing function.

In the case of linear equations, the graph will always be a line. In contrast, a nonlinear equation may look like a parabola if it is of degree 2, a curvy x-shape if it is of degree 3, or any curvy variation thereof. While linear equations are always straight, nonlinear equations often feature curves.