Chapter 10: Problem 12
Evaluate each function at the given point. \(g\left(x_{1}, x_{2}, x_{3}, x_{4}\right)=x_{1} x_{4} \sqrt{x_{2} x_{3}}\) at \((1,8,2,-1)\)
Short Answer
Expert verified
The function evaluates to -4.
Step by step solution
01
Understand the function
The function given is a multivariable function: \(g(x_1, x_2, x_3, x_4) = x_1 x_4 \sqrt{x_2 x_3}\). It involves four variables \(x_1, x_2, x_3,\) and \(x_4\). The expression includes a product of these variables and the square root of their product.
02
Identify each variable
Here, you need to substitute the values \(x_1 = 1\), \(x_2 = 8\), \(x_3 = 2\), and \(x_4 = -1\) into the function. These are the specific inputs given for this exercise.
03
Substitute and simplify under the square root
Calculate the expression under the square root: \(\sqrt{x_2 x_3} = \sqrt{8 \times 2}\). First, compute the product inside the root: \(8 \times 2 = 16\). Then, find the square root: \(\sqrt{16} = 4\).
04
Evaluate the entire function
Now substitute all values into the function: \(g(x_1, x_2, x_3, x_4) = 1 \times (-1) \times 4\). Compute the product: \(1 \times (-1) \times 4 = -4\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Evaluate Functions
Evaluating a function means determining its output when specific values are assigned to its variables. In this case, we're looking at the function \(g(x_1, x_2, x_3, x_4) = x_1 x_4 \sqrt{x_2 x_3}\). To evaluate this function at a specific point, such as \((1,8,2,-1)\), follow these steps:
- Understand the structure of the function and what it represents.
- Identify which values correspond to each variable. Here, \(x_1 = 1\), \(x_2 = 8\), \(x_3 = 2\), and \(x_4 = -1\).
- Substitute these values into the function and simplify the expression.
- Perform operations such as multiplication, division, and finding square roots as required.
- The final outcome is your evaluated function value.
Multivariable Functions
A multivariable function is where more than one input variable affects the output. Here, we work with the function \(g(x_1, x_2, x_3, x_4)\). Such functions are common in calculus involving several dimensions. They help model real-world issues more accurately as most phenomena depend on multiple factors. Some key points about multivariable functions include:
- They can have countless applications, from engineering problems to economics and physics.
- Each variable in the function holds a unique value or dimension, influencing the overall output.
- Understanding these functions requires handling multiple inputs simultaneously and seeing how they interact in the function.
- These functions often produce surfaces or curves when graphed, offering visual insights into their behavior.
Functions of Several Variables
Functions of several variables, like the one we examined \(g(x_1, x_2, x_3, x_4)\), involve more than one independent variable which influences the dependent outcome. Unlike single-variable functions that involve one-dimensional lines, these functions create more complex surfaces.Being adept in dealing with several variables requires keen skill in
- Spotting the role of each variable and how it contributes to the function's output.
- Evaluating the combined effect of these variables, such as using multiplication and operations like square roots in our example.
- Visualizing how changes in one variable influence the result, offering a better grip on dynamic systems.
- Often, it's essential to understand the concept of partial derivatives, which show how the function changes as one of the inputs changes, holding others constant.