Vertical Tangent Line: A vertical tangent line is a line that is perpendicular to the curve of a function at a specific point and has an undefined slope. It occurs when there is an abrupt change in direction or when the slope becomes infinite.
Smooth: In calculus, smooth refers to functions that are continuous and have no sharp corners or breaks in their graph. They exhibit gradual changes and have no abrupt changes in direction.
Piecewise Function: A piecewise function is made up of different equations defined for different intervals or pieces of the domain. It's like having multiple gears on a bike - each gear represents a different equation used to describe the function within its specific interval.