Why Is There Only One Stationary Point for the Volume of This Box?

In summary, the volume of a box is given by the equation V=4x^3-66x^2+216x, where x represents the length of the sides of the box. To find the stationary point, we take the derivative of V with respect to x and set it equal to zero. This results in the equation x^2-11x+18=0, with solutions x=2 and x=9. However, since a box cannot have a negative volume, the only reasonable solution is x=2. Therefore, there is only one value of x for which V is stationary.
  • #1
Andy21
20
0

Homework Statement


The volume of a box is given by V=4x^3 -66x^2 +216x. Explain why there is only one value of x for which V is stationary?


Homework Equations





The Attempt at a Solution


dV/dx = 12x^2 -132x +216 at a stationary point x^2-11x+18=0 so x=2 or 9
 
Last edited:
Physics news on Phys.org
  • #2
You need to check if those solutions are reasonable since you're talking about a physical situation. What are the volumes for those two points?
 
  • #3
I got a volume of -486 for x=9 and 200 for x=2. I think that the one stationary point must be at x=2 because a box can't have a negative volume. Is this correct?
 
  • #4
Yes, that's exactly it.
 
  • #5
Thanks for the help
 

FAQ: Why Is There Only One Stationary Point for the Volume of This Box?

What is differentiation?

Differentiation is a mathematical concept that refers to the process of finding the rate of change of a function with respect to its independent variable. It is essentially the process of finding the slope of a curve at a specific point.

Why is differentiation important?

Differentiation is important because it allows us to analyze the behavior of functions and understand how they change. It is used in many fields such as physics, engineering, economics, and more to model and solve real-world problems.

What is the basic formula for differentiation?

The basic formula for differentiation is dy/dx, which represents the derivative of the function y with respect to the independent variable x. This formula gives us the slope of the curve at any given point.

How do you differentiate a function?

To differentiate a function, we use a set of rules and formulas to find the derivative. These rules include the power rule, product rule, quotient rule, and chain rule. By applying these rules to the function, we can find the derivative and determine the slope of the curve at any point.

What are some practical applications of differentiation?

Differentiation has many practical applications, such as predicting future trends in economics, optimizing production processes in engineering, and understanding the motion of objects in physics. It is also used in finance, biology, and many other fields to model and analyze various phenomena.

Back
Top