Math Problem Statement

The image contains four math problems related to function equivalence, one-to-one functions, inverse functions, and composition of functions.

Solution

Let's work through the problems step by step.

A. Determine whether the following functions are the same or not:

  • f(x)=x+1+x2f(x) = \sqrt{x} + 1 + \sqrt{x-2}
  • g(x)=(x+1)(x2)g(x) = \sqrt{(x+1)(x-2)}

Solution:

1. f(x)=x+1+x2f(x) = \sqrt{x} + 1 + \sqrt{x - 2}:

For f(x)f(x), we have two square roots and a constant added: f(x)=x+1+x2f(x) = \sqrt{x} + 1 + \sqrt{x-2} This function is only defined for x2x \geq 2, because x2\sqrt{x-2} is undefined for x<2x < 2.

2. g(x)=(x+1)(x2)g(x) = \sqrt{(x+1)(x-2)}:

Here, g(x)g(x) involves a square root of a product of two terms: g(x)=(x+1)(x2)g(x) = \sqrt{(x+1)(x-2)} We can expand (x+1)(x2)(x+1)(x-2) as: (x+1)(x2)=x22x+x2=x2x2(x+1)(x-2) = x^2 - 2x + x - 2 = x^2 - x - 2 Thus, g(x)=x2x2g(x) = \sqrt{x^2 - x - 2}.

Since x2x2\sqrt{x^2 - x - 2} is not equivalent to the form of f(x)f(x) after simplification, the two functions are not the same.


B. Determine whether the following functions are one-to-one or not:

i) f(x)=1x2,  0x1f(x) = \sqrt{1 - x^2}, \; 0 \leq x \leq 1

This is the upper half of a semicircle with radius 1. Since it's restricted to 0x10 \leq x \leq 1, the function is not one-to-one, as the function does not have a unique output for each input over a larger domain, but within this domain it is fine.

ii) f(x)=3(5+x)1/7f(x) = 3 - (5 + x)^{1/7}

This is a decreasing function because of the negative exponent. As it is strictly decreasing, the function is one-to-one.

iii) f(x)=cos(x)f(x) = \cos(x)

The cosine function is periodic and repeats its values over its domain, so it is not one-to-one.


C. Assume that f(x)=1x33f(x) = \sqrt[3]{1 - x^3} is a one-to-one function:

i) Find f1f^{-1}:

To find the inverse, start by setting y=f(x)y = f(x): y=1x33y = \sqrt[3]{1 - x^3} Now, cube both sides: y3=1x3y^3 = 1 - x^3 Solving for x3x^3: x3=1y3x^3 = 1 - y^3 Now take the cube root: x=1y33x = \sqrt[3]{1 - y^3} Thus, the inverse function is: f1(x)=1x33f^{-1}(x) = \sqrt[3]{1 - x^3}

ii) Domain and range of f1f^{-1}:

  • The domain of f(x)f(x) (original function) is all real numbers because cube roots are defined for all real values.
  • The range of f(x)f(x) is also all real numbers because 1x33\sqrt[3]{1 - x^3} can take any real value.

Therefore, the domain and range of f1(x)f^{-1}(x) are both all real numbers (,)(-\infty, \infty).


D. Write the function h(x)=1(x2)3h(x) = \frac{1}{(x - 2)^3} as a composition of two functions.

Let:

  • u(x)=x2u(x) = x - 2
  • v(u)=1u3v(u) = \frac{1}{u^3}

Thus, we can write: h(x)=v(u(x))=1(x2)3h(x) = v(u(x)) = \frac{1}{(x - 2)^3} So the function can be written as: h(x)=v(u(x))h(x) = v(u(x))


If you would like any further explanations, feel free to ask!

Here are 5 related questions for practice:

  1. How do you verify if two functions are equal?
  2. How can you determine if a function is one-to-one by using its derivative?
  3. What is the general method for finding the inverse of a function?
  4. What is the difference between the domain and range of a function and its inverse?
  5. How can you decompose a more complex function into simpler functions?

Tip: Always check the domain restrictions when determining if two functions are equal!

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Math Problem Analysis

Mathematical Concepts

Function Comparison
One-to-One Functions
Inverse Functions
Function Composition

Formulas

f(x) = sqrt(x) + 1 + sqrt(x-2)
g(x) = sqrt((x+1)(x-2))
Inverse Function Formula: y = f(x), solve for x in terms of y
Composition Formula: h(x) = v(u(x))

Theorems

Inverse Function Theorem
One-to-One Function Theorem

Suitable Grade Level

College Level