Math Problem Statement

) (15 points) Let f (x) = xe2−x and g(x) = x e 2−x . Find where f (x) < g(x) by answering the questions below. Show all your work in each step. a) Find a function h such that solving h(x) < 0 will solve the original problem of f (x) < g(x). h(x) = b) Find the domain of h in interval notation.

Solution

Problem Breakdown

We are tasked with comparing two functions:

  • f(x)=xe2xf(x) = x e^{2 - x}
  • g(x)=xe2xg(x) = x e^{2 - x}

Let's analyze the problem step by step.

Part a) Find a function h(x)h(x) such that solving h(x)<0h(x) < 0 will solve the original problem of f(x)<g(x)f(x) < g(x).

We are looking for the values of xx where f(x)f(x) is less than g(x)g(x), i.e.,

f(x)<g(x)f(x) < g(x)

Subtract g(x)g(x) from both sides to form a new function h(x)h(x):

f(x)g(x)<0f(x) - g(x) < 0

Notice that:

f(x)=xe2xf(x) = x e^{2 - x} g(x)=xe2xg(x) = x e^{2 - x}

So, f(x)g(x)=0f(x) - g(x) = 0.

This shows that:

f(x)=g(x)f(x) = g(x)

for all values of xx, meaning that f(x)f(x) is never less than g(x)g(x), and hence no such xx exists where f(x)<g(x)f(x) < g(x).

Therefore, there is no solution for f(x)<g(x)f(x) < g(x). In other words, the inequality f(x)<g(x)f(x) < g(x) does not hold for any value of xx.

Part b) Find the domain of h(x)h(x) in interval notation.

Since h(x)=f(x)g(x)=0h(x) = f(x) - g(x) = 0 for all xx, there is no domain restriction for h(x)h(x) because it is simply the constant function 0. Therefore, the domain of h(x)h(x) is the same as the domain of the original functions f(x)f(x) and g(x)g(x), which is all real numbers.

Thus, the domain of h(x)h(x) is:

(,)(-\infty, \infty)

Summary

  • a) The function h(x)h(x) is 00 because f(x)=g(x)f(x) = g(x) for all xx. Therefore, there is no solution to the inequality f(x)<g(x)f(x) < g(x).
  • b) The domain of h(x)h(x) is (,)(-\infty, \infty).

Would you like a further explanation or have any other questions on this? Here's a related set of questions for further practice:

  1. What happens when f(x)=g(x)f(x) = g(x)?
  2. How can we compare functions if they have similar forms, but slightly different expressions?
  3. Can a function like f(x)f(x) and g(x)g(x) ever be strictly greater than or less than each other? Why or why not?
  4. How do exponential terms impact the comparison of functions?
  5. If f(x)g(x)f(x) \neq g(x), how would you approach finding where f(x)<g(x)f(x) < g(x)?

Tip: When comparing two functions, always subtract them first to see if the result simplifies the inequality or if it reveals a relationship between the two.

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Math Problem Analysis

Mathematical Concepts

Inequalities
Exponential Functions
Function Comparison

Formulas

f(x) = x * e^(2 - x)
g(x) = x * e^(2 - x)
h(x) = f(x) - g(x)

Theorems

Function comparison
Exponential function properties

Suitable Grade Level

Grades 11-12