Math Problem Statement

Let g, of, xg(x) and h, of, xh(x) be defined by g, of, x, equals, minus, 2, x, squared, plus, 4, xg(x)=−2x 2 +4x and h, of, x, equals, 16, x, plus, 18h(x)=16x+18. If f, of, xf(x) is a function such that g, of, x, is less than or equal to, f, of, x, is less than or equal to, h, of, xg(x)≤f(x)≤h(x), find limit, start subscript, x, right arrow, minus, 3, end subscript, f, of, x x→−3 lim ​ f(x), or state that it cannot be determined.

Solution

We are given two functions, g(x)=2x2+4xg(x) = -2x^2 + 4x and h(x)=16x+18h(x) = 16x + 18, along with an inequality g(x)f(x)h(x)g(x) \leq f(x) \leq h(x). We are tasked with finding:

limx3f(x)\lim_{x \to -3} f(x)

Step 1: Compute limx3g(x)\lim_{x \to -3} g(x)

We begin by finding the limit of g(x)g(x) as xx approaches -3:

g(x)=2x2+4xg(x) = -2x^2 + 4x

Substitute x=3x = -3 into g(x)g(x):

g(3)=2(3)2+4(3)=2(9)12=1812=30g(-3) = -2(-3)^2 + 4(-3) = -2(9) - 12 = -18 - 12 = -30

Thus, limx3g(x)=30\lim_{x \to -3} g(x) = -30.

Step 2: Compute limx3h(x)\lim_{x \to -3} h(x)

Next, we find the limit of h(x)h(x) as xx approaches -3:

h(x)=16x+18h(x) = 16x + 18

Substitute x=3x = -3 into h(x)h(x):

h(3)=16(3)+18=48+18=30h(-3) = 16(-3) + 18 = -48 + 18 = -30

Thus, limx3h(x)=30\lim_{x \to -3} h(x) = -30.

Step 3: Apply the Squeeze Theorem

Since g(x)f(x)h(x)g(x) \leq f(x) \leq h(x), and both limx3g(x)=30\lim_{x \to -3} g(x) = -30 and limx3h(x)=30\lim_{x \to -3} h(x) = -30, by the Squeeze Theorem, we can conclude that:

limx3f(x)=30\lim_{x \to -3} f(x) = -30

Thus, the limit is 30-30.

Conclusion:

limx3f(x)=30\lim_{x \to -3} f(x) = -30


Would you like more details or have any questions?

Here are five related questions to explore:

  1. What is the Squeeze Theorem, and how is it used in limit problems?
  2. How can we find the limit of a quadratic function?
  3. What happens when a function is bounded by two other functions?
  4. How can we verify if the Squeeze Theorem applies in other scenarios?
  5. How do you compute limits for piecewise functions?

Tip: When dealing with limits involving inequalities, always check if the Squeeze Theorem can help simplify the problem.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Limits
Quadratic Functions
Linear Functions
Squeeze Theorem

Formulas

g(x) = −2x^2 + 4x
h(x) = 16x + 18
Squeeze Theorem: If g(x) ≤ f(x) ≤ h(x) and lim(x→c) g(x) = lim(x→c) h(x) = L, then lim(x→c) f(x) = L

Theorems

Squeeze Theorem

Suitable Grade Level

Grades 10-12