Question #7943
If you are provided with a polynomial function of degree three or greater, what are some ways you could explain the behavior without graphing the function? Which of your invented methods is best? Why?
Expert's answer
The best way to explain the behaviour of the polynomial function of
degree three or greater is to analyze the derivatives of this function.
The standard way to explore the behaviour is:
1). find the nulls of polynomial
2). study the sign of the first derivative
3). study the sign of the second derivative
Analyzing this information you'll get the intervals of increase, decrease and concavity of polynomial.
Knowing
nulls of polynomial, you'll know where function is positive or
negative. From the second step( studying the sign of the first
derivative) you can find out what are the intervals of increase and
decrease and also critical points(points which can be points of maximum
or minimum). From the third step(studying the sign of the second
derivative) you'll find intervals of concavity and also turning points.
degree three or greater is to analyze the derivatives of this function.
The standard way to explore the behaviour is:
1). find the nulls of polynomial
2). study the sign of the first derivative
3). study the sign of the second derivative
Analyzing this information you'll get the intervals of increase, decrease and concavity of polynomial.
Knowing
nulls of polynomial, you'll know where function is positive or
negative. From the second step( studying the sign of the first
derivative) you can find out what are the intervals of increase and
decrease and also critical points(points which can be points of maximum
or minimum). From the third step(studying the sign of the second
derivative) you'll find intervals of concavity and also turning points.
