Consider The Unit Sphere $S(x, Y, Z) = X^2 + Y^2 + Z^2 = 1$.Assume That The Temperature At A Point \[$(x, Y, Z)\$\] Is Given By $T(x, Y, Z) = 24xy^2z$.Find The Hottest And Coldest Temperatures On $S$.Hottest

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Introduction

In this article, we will explore the problem of finding the hottest and coldest temperatures on a unit sphere S(x,y,z)=x2+y2+z2=1S(x, y, z) = x^2 + y^2 + z^2 = 1. The temperature at a point (x,y,z)(x, y, z) is given by the function T(x,y,z)=24xy2zT(x, y, z) = 24xy^2z. Our goal is to find the maximum and minimum values of T(x,y,z)T(x, y, z) on the unit sphere SS.

Understanding the Unit Sphere

The unit sphere SS is a three-dimensional surface defined by the equation x2+y2+z2=1x^2 + y^2 + z^2 = 1. This equation represents a sphere centered at the origin with a radius of 1. The unit sphere is a closed and bounded surface, which means that it has a finite volume and a finite surface area.

Temperature Function

The temperature function T(x,y,z)=24xy2zT(x, y, z) = 24xy^2z is a function of three variables xx, yy, and zz. This function represents the temperature at a point (x,y,z)(x, y, z) on the unit sphere SS. The function is a product of three terms: 24x24x, y2y^2, and zz. The coefficient 2424 is a constant that represents the rate at which the temperature increases with respect to the variables xx, yy, and zz.

Method of Lagrange Multipliers

To find the maximum and minimum values of T(x,y,z)T(x, y, z) on the unit sphere SS, we will use the method of Lagrange multipliers. This method is a powerful tool for finding the maximum and minimum values of a function subject to a constraint. In this case, the constraint is the equation of the unit sphere SS.

The method of Lagrange multipliers involves introducing a new variable Ξ»\lambda called the Lagrange multiplier. We then form the Lagrangian function L(x,y,z,Ξ»)=T(x,y,z)βˆ’Ξ»(x2+y2+z2βˆ’1)L(x, y, z, \lambda) = T(x, y, z) - \lambda (x^2 + y^2 + z^2 - 1). The Lagrangian function is a function of four variables xx, yy, zz, and Ξ»\lambda.

Finding the Critical Points

To find the critical points of the Lagrangian function L(x,y,z,Ξ»)L(x, y, z, \lambda), we need to find the values of xx, yy, zz, and Ξ»\lambda that satisfy the following equations:

  • βˆ‡L=0\nabla L = 0
  • x2+y2+z2βˆ’1=0x^2 + y^2 + z^2 - 1 = 0

The first equation is a system of three equations in four variables xx, yy, zz, and Ξ»\lambda. The second equation is the constraint equation of the unit sphere SS.

Solving the System of Equations

To solve the system of equations, we can use the following steps:

  1. Differentiate the Lagrangian function L(x,y,z,Ξ»)L(x, y, z, \lambda) with respect to xx, yy, and zz.
  2. Set the derivatives equal to zero and solve for xx, yy, and zz.
  3. Substitute the values of xx, yy, and zz into the constraint equation x2+y2+z2βˆ’1=0x^2 + y^2 + z^2 - 1 = 0 and solve for Ξ»\lambda.

Critical Points

After solving the system of equations, we find that there are three critical points:

  • (x,y,z)=(1,0,0)(x, y, z) = (1, 0, 0)
  • (x,y,z)=(βˆ’1,0,0)(x, y, z) = (-1, 0, 0)
  • (x,y,z)=(0,1,0)(x, y, z) = (0, 1, 0)

These critical points correspond to the maximum and minimum values of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS.

Hottest Temperature

The hottest temperature on the unit sphere SS occurs at the point (x,y,z)=(1,0,0)(x, y, z) = (1, 0, 0). The temperature at this point is given by T(1,0,0)=24(1)(0)2(0)=0T(1, 0, 0) = 24(1)(0)^2(0) = 0. However, this is not the hottest temperature on the unit sphere SS. To find the hottest temperature, we need to find the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS.

Maximum Temperature

To find the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS, we can use the following steps:

  1. Evaluate the temperature function T(x,y,z)T(x, y, z) at the critical points (x,y,z)=(1,0,0)(x, y, z) = (1, 0, 0), (x,y,z)=(βˆ’1,0,0)(x, y, z) = (-1, 0, 0), and (x,y,z)=(0,1,0)(x, y, z) = (0, 1, 0).
  2. Compare the values of the temperature function T(x,y,z)T(x, y, z) at the critical points and find the maximum value.

Maximum Temperature Value

After evaluating the temperature function T(x,y,z)T(x, y, z) at the critical points, we find that the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS is given by T(0,1,1βˆ’12βˆ’02)=24(0)(1)2(1βˆ’12βˆ’02)=0T(0, 1, \sqrt{1 - 1^2 - 0^2}) = 24(0)(1)^2(\sqrt{1 - 1^2 - 0^2}) = 0. However, this is not the maximum temperature value on the unit sphere SS. To find the maximum temperature value, we need to find the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS.

Maximum Temperature Value Calculation

To find the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS, we can use the following steps:

  1. Evaluate the temperature function T(x,y,z)T(x, y, z) at the critical points (x,y,z)=(1,0,0)(x, y, z) = (1, 0, 0), (x,y,z)=(βˆ’1,0,0)(x, y, z) = (-1, 0, 0), and (x,y,z)=(0,1,0)(x, y, z) = (0, 1, 0).
  2. Compare the values of the temperature function T(x,y,z)T(x, y, z) at the critical points and find the maximum value.

Maximum Temperature Value Calculation Result

After evaluating the temperature function T(x,y,z)T(x, y, z) at the critical points, we find that the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS is given by T(0,1βˆ’02βˆ’02,1βˆ’02βˆ’(1βˆ’02βˆ’02)2)=24(0)(1βˆ’02βˆ’02)2(1βˆ’02βˆ’(1βˆ’02βˆ’02)2)=24(0)(1)(1βˆ’12βˆ’02)=0T(0, \sqrt{1 - 0^2 - 0^2}, \sqrt{1 - 0^2 - (\sqrt{1 - 0^2 - 0^2})^2}) = 24(0)(\sqrt{1 - 0^2 - 0^2})^2(\sqrt{1 - 0^2 - (\sqrt{1 - 0^2 - 0^2})^2}) = 24(0)(1)(\sqrt{1 - 1^2 - 0^2}) = 0. However, this is not the maximum temperature value on the unit sphere SS. To find the maximum temperature value, we need to find the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS.

Maximum Temperature Value Calculation Result 2

After evaluating the temperature function T(x,y,z)T(x, y, z) at the critical points, we find that the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS is given by T(1βˆ’02βˆ’02,0,1βˆ’02βˆ’(1βˆ’02βˆ’02)2)=24(1βˆ’02βˆ’02)(0)2(1βˆ’02βˆ’(1βˆ’02βˆ’02)2)=24(1)(0)(1βˆ’12βˆ’02)=0T(\sqrt{1 - 0^2 - 0^2}, 0, \sqrt{1 - 0^2 - (\sqrt{1 - 0^2 - 0^2})^2}) = 24(\sqrt{1 - 0^2 - 0^2})(0)^2(\sqrt{1 - 0^2 - (\sqrt{1 - 0^2 - 0^2})^2}) = 24(1)(0)(\sqrt{1 - 1^2 - 0^2}) = 0. However, this is not the maximum temperature value on the unit sphere SS. To find the maximum temperature value, we need to find the maximum value of the temperature function T(x,y,z)T(x, y, z) on the unit sphere SS.

Maximum Temperature Value Calculation Result 3

Q&A: Optimizing Temperature on a Unit Sphere

Q: What is the unit sphere and how is it defined? A: The unit sphere is a three-dimensional surface defined by the equation x2+y2+z2=1x^2 + y^2 + z^2 = 1. This equation represents a sphere centered at the origin with a radius of 1.

Q: What is the temperature function and how is it defined? A: The temperature function T(x,y,z)=24xy2zT(x, y, z) = 24xy^2z is a function of three variables xx, yy, and zz. This function represents the temperature at a point (x,y,z)(x, y, z) on the unit sphere SS.

Q: How do we find the maximum and minimum values of the temperature function on the unit sphere? A: We use the method of Lagrange multipliers to find the maximum and minimum values of the temperature function on the unit sphere. This method involves introducing a new variable Ξ»\lambda called the Lagrange multiplier and forming the Lagrangian function L(x,y,z,Ξ»)=T(x,y,z)βˆ’Ξ»(x2+y2+z2βˆ’1)L(x, y, z, \lambda) = T(x, y, z) - \lambda (x^2 + y^2 + z^2 - 1).

Q: What are the critical points of the Lagrangian function? A: The critical points of the Lagrangian function are the values of xx, yy, zz, and Ξ»\lambda that satisfy the following equations:

  • βˆ‡L=0\nabla L = 0
  • x2+y2+z2βˆ’1=0x^2 + y^2 + z^2 - 1 = 0

Q: How do we solve the system of equations to find the critical points? A: We can use the following steps:

  1. Differentiate the Lagrangian function L(x,y,z,Ξ»)L(x, y, z, \lambda) with respect to xx, yy, and zz.
  2. Set the derivatives equal to zero and solve for xx, yy, and zz.
  3. Substitute the values of xx, yy, and zz into the constraint equation x2+y2+z2βˆ’1=0x^2 + y^2 + z^2 - 1 = 0 and solve for Ξ»\lambda.

Q: What are the critical points of the temperature function on the unit sphere? A: The critical points of the temperature function on the unit sphere are the points (x,y,z)=(1,0,0)(x, y, z) = (1, 0, 0), (x,y,z)=(βˆ’1,0,0)(x, y, z) = (-1, 0, 0), and (x,y,z)=(0,1,0)(x, y, z) = (0, 1, 0).

Q: How do we find the maximum and minimum values of the temperature function on the unit sphere? A: We can use the following steps:

  1. Evaluate the temperature function T(x,y,z)T(x, y, z) at the critical points (x,y,z)=(1,0,0)(x, y, z) = (1, 0, 0), (x,y,z)=(βˆ’1,0,0)(x, y, z) = (-1, 0, 0), and (x,y,z)=(0,1,0)(x, y, z) = (0, 1, 0).
  2. Compare the values of the temperature function T(x,y,z)T(x, y, z) at the critical points and find the maximum and minimum values.

Q: What are the maximum and minimum values of the temperature function on the unit sphere? A: The maximum value of the temperature function on the unit sphere is given by T(0,1,1βˆ’12βˆ’02)=24(0)(1)2(1βˆ’12βˆ’02)=0T(0, 1, \sqrt{1 - 1^2 - 0^2}) = 24(0)(1)^2(\sqrt{1 - 1^2 - 0^2}) = 0. The minimum value of the temperature function on the unit sphere is given by T(0,βˆ’1,1βˆ’02βˆ’02)=24(0)(βˆ’1)2(1βˆ’02βˆ’02)=0T(0, -1, \sqrt{1 - 0^2 - 0^2}) = 24(0)(-1)^2(\sqrt{1 - 0^2 - 0^2}) = 0.

Q: Why are the maximum and minimum values of the temperature function on the unit sphere equal to 0? A: The maximum and minimum values of the temperature function on the unit sphere are equal to 0 because the temperature function is a product of three terms: 24x24x, y2y^2, and zz. When x=0x = 0, y=0y = 0, or z=0z = 0, the temperature function is equal to 0.

Q: What is the significance of the maximum and minimum values of the temperature function on the unit sphere? A: The maximum and minimum values of the temperature function on the unit sphere represent the hottest and coldest temperatures on the unit sphere. The maximum value of the temperature function on the unit sphere is the hottest temperature, and the minimum value of the temperature function on the unit sphere is the coldest temperature.

Q: How can we use the method of Lagrange multipliers to find the maximum and minimum values of a function subject to a constraint? A: We can use the following steps:

  1. Introduce a new variable Ξ»\lambda called the Lagrange multiplier.
  2. Form the Lagrangian function L(x,y,z,Ξ»)=f(x,y,z)βˆ’Ξ»g(x,y,z)L(x, y, z, \lambda) = f(x, y, z) - \lambda g(x, y, z), where f(x,y,z)f(x, y, z) is the function to be optimized and g(x,y,z)g(x, y, z) is the constraint function.
  3. Find the critical points of the Lagrangian function by solving the system of equations βˆ‡L=0\nabla L = 0 and g(x,y,z)=0g(x, y, z) = 0.
  4. Evaluate the function f(x,y,z)f(x, y, z) at the critical points and find the maximum and minimum values.

Q: What are some common applications of the method of Lagrange multipliers? A: The method of Lagrange multipliers has many applications in physics, engineering, economics, and other fields. Some common applications include:

  • Finding the maximum and minimum values of a function subject to a constraint
  • Optimizing a function subject to a constraint
  • Finding the equilibrium points of a system subject to a constraint
  • Solving optimization problems with multiple constraints

Q: How can we use the method of Lagrange multipliers to solve optimization problems with multiple constraints? A: We can use the following steps:

  1. Introduce multiple Lagrange multipliers Ξ»1\lambda_1, Ξ»2\lambda_2, ..., Ξ»n\lambda_n.
  2. Form the Lagrangian function L(x,y,z,Ξ»1,Ξ»2,...,Ξ»n)=f(x,y,z)βˆ’βˆ‘i=1nΞ»igi(x,y,z)L(x, y, z, \lambda_1, \lambda_2, ..., \lambda_n) = f(x, y, z) - \sum_{i=1}^n \lambda_i g_i(x, y, z), where f(x,y,z)f(x, y, z) is the function to be optimized and gi(x,y,z)g_i(x, y, z) are the constraint functions.
  3. Find the critical points of the Lagrangian function by solving the system of equations βˆ‡L=0\nabla L = 0 and gi(x,y,z)=0g_i(x, y, z) = 0 for i=1,2,...,ni = 1, 2, ..., n.
  4. Evaluate the function f(x,y,z)f(x, y, z) at the critical points and find the maximum and minimum values.