How different polynomial and non polynomial?
Well, "non-polynomial" can be just about anything; presumably
you mean a non-polynomial FUNCTION, but there are lots of different
types of functions. Polynomials, among other things, have the
following properties - assuming you have an expression of the type
y = P(x):* The polynomial is defined for any value of "x".
* The polynomial makes is continuous; i.e., it doesn't make
sudden "jumps".
* Similarly, the first derivative, the second derivative, etc.,
are continuous.
A non-polynomial function may not have all of these properties;
for example:
* A rational function is not defined at any point where the
denominator is zero.
* The square root function is not defined for negative
values.
* The first derivative (i.e., the slope) of the absolute value
function makes a sudden jump at x = 0.
* The function that takes the integer part of any real number
makes sudden jumps at all integers.