Rate of change:
In the function of y = f (x)
x is independent variable, y is the dependent variable.
If the slope of a line equal to m,
A function is continuous at a point when the graph passes through the point without a break. If the graph has a break of some type at a point, then the graph is not continuous (discontinuous) at this point.
The function f (x) is continuous at x = a
P(x) = anxn + an-1xn-1 + ...a1x + a0
a0, a1, a2...an are constant.
All the polynomial functions are have limits at all real values.
All the polynomial functions are continuous at all real values.
Every rational functions are continuous except at a value: Q(a) = 0