Math Problem Statement

Given a function g(x) = 2x^2 + 3, then an inverse of the function defined as g^{-1}(x) exists. True or False?

Solution

The given function is g(x)=2x2+3g(x) = 2x^2 + 3. The question asks whether the inverse of this function, g1(x)g^{-1}(x), exists.

To check if the inverse exists:

For a function to have an inverse, it must be bijective:

  1. Injective (One-to-one): Every input must map to a unique output.
  2. Surjective (Onto): The function must cover the entire range of possible outputs.

Since g(x)=2x2+3g(x) = 2x^2 + 3 is a quadratic function, its graph is a parabola, and parabolas are not injective because they are symmetric. In other words, for any value of g(x)g(x), there are two possible values of xx (one positive and one negative) that could map to the same output.

For example:

  • If g(x1)=g(x2)g(x_1) = g(x_2), then 2x12+3=2x22+32x_1^2 + 3 = 2x_2^2 + 3, which simplifies to x12=x22x_1^2 = x_2^2. Therefore, x1=±x2x_1 = \pm x_2.

This means the function is not one-to-one (injective), and thus it does not have an inverse without further restrictions, like limiting the domain.

Conclusion:

The inverse function g1(x)g^{-1}(x) does not exist as the function g(x)=2x2+3g(x) = 2x^2 + 3 is not injective.

Answer: False

Would you like further details on this or any related concept? Here are 5 follow-up questions for deeper understanding:

  1. What is the difference between injective and surjective functions?
  2. How can you restrict the domain of a function to make it invertible?
  3. Can you calculate the inverse of a quadratic function if the domain is restricted?
  4. How do you graphically determine whether a function has an inverse?
  5. What are the necessary conditions for a function to be considered bijective?

Tip: Always remember to check if a function is one-to-one before determining if an inverse exists.

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Math Problem Analysis

Mathematical Concepts

Algebra
Inverse Functions
Quadratic Functions
Bijective Functions

Formulas

g(x) = 2x^2 + 3
x^2 = (y - 3)/2

Theorems

Conditions for Inverse Functions
Injectivity of Functions

Suitable Grade Level

Grades 9-12