# Does every cubic function have a maximum and minimum?

## Does every cubic function have a maximum and minimum?

All cubic functions (or cubic polynomials) have at least one real zero (also called ‘root’). This is a consequence of the Bolzano’s Theorem or the Fundamental Theorem of Algebra. Any cubic function has an inflection point. Sometimes, a cubic function has a maximum and a minimum.

Can a function have no max or min?

A function does not have an extreme value (Maximum or Minimum) when it is a constant function (y=c or x=c). A bit more : The derivative of the function is 0, and the double derivative of the function does not exist or is 0 too.

### Can a cubic function have no Extrema?

Since a cubic function can’t have more than two critical points, it certainly can’t have more than two extreme values. Also, a cubic function cannot have just one local extremum except in the slightly dumb case when a = 0 (in which case it’s really a quadratic function instead of a cubic).

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Can a cubic function have no turning points?

In particular, a cubic graph goes to −∞ in one direction and +∞ in the other. So it must cross the x-axis at least once. Furthermore, all the examples of cubic graphs have precisely zero or two turning points, an even number.

## Does a cubic function have a minimum?

The graph of a cubic function always has a single inflection point. It may have two critical points, a local minimum and a local maximum.

Can a function not have a minimum?

Notice also that a function does not have to have any global or local maximum, or global or local minimum. Example: f(x)=3x + 4 f has no local or global max or min.

### How do you know when there is no maximum?

Here are the rules:

• If the graph has a gap at the x value c, then the two-sided limit at that point will not exist.
• If the graph has a vertical asymptote and one side of the asymptote goes toward infinity and the other goes toward negative infinity, then the limit does not exist.

How do you find the critical points of a cubic function?

The critical points of a cubic equation are those values of x where the slope of the cubic function is zero. They are found by setting derivative of the cubic equation equal to zero obtaining: f ′(x) = 3ax2 + 2bx + c = 0. The solutions of that equation are the critical points of the cubic equation.

## How do you find the minimum and maximum turning points?

First, identify the leading term of the polynomial function if the function were expanded. Then, identify the degree of the polynomial function. This polynomial function is of degree 4. The maximum number of turning points is 4 – 1 = 3.

How many turning points does a cubic graph have?

2 turning points
Cubic functions can have at most 3 real roots (including multiplicities) and 2 turning points.

### When does a cubic function have no maximum and minimum?

A cubic function has no maximum and minimum when its derivative (which is a quadratic) has either no real roots or has two equal roots. and this has less than two distinct roots whenever [math](2b)^2 leq 4(3a)cmath], or when [math]b^2 leq 3ac[/math].

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Can a graph have maximum and minimums but not maximums?

So, some graphs can have minimums but not maximums. Likewise, a graph could have maximums but not minimums. Here is the graph for this function. This function has an absolute maximum of eight at x = 2 x = 2 and an absolute minimum of negative eight at x = − 2 x = − 2.

## What is a local maximum and local minimum in calculus?

When a function’s slope is zero at x, and the second derivative at x is: less than 0, it is a local maximum. greater than 0, it is a local minimum.

What is the maximum and minimum of the derivative at 0?

The derivative of f is f ′ ( x) = 3 x 2, and f ′ ( 0) = 0, but there is neither a maximum nor minimum at ( 0, 0) . Figure 5.1.2. No maximum or minimum even though the derivative is zero. Since the derivative is zero or undefined at both local maximum and local minimum points, we need a way to determine which, if either, actually occurs.