Increasing Function: A function is increasing if its derivative is positive at every point. It means that as the independent variable increases, the dependent variable also increases.
Zero Derivative: When a function has a zero derivative at a specific point, it means that there is no change in the function's value at that point. The curve appears flat or horizontal.
Decreasing Function: A function is decreasing if its derivative is negative at every point. This means that as the independent variable increases, the dependent variable decreases.