Math Problem Statement

Given the functions f(x) = √(x + 3), g(x) = 6/x, and h(x) = x^2, write a simplified formula for the new function based on (f ∘ g ∘ h)(x) and determine its domain.

Solution

The image provided shows the problem asking to find the formula for the new function formed by the composition (fgh)(x)(f \circ g \circ h)(x), where the given functions are:

f(x)=x+3,g(x)=6x,h(x)=x2.f(x) = \sqrt{x+3}, \quad g(x) = \frac{6}{x}, \quad h(x) = x^2.

Let's break down the composition step-by-step:

1. Compute (gh)(x)(g \circ h)(x):

We need to substitute h(x)=x2h(x) = x^2 into g(x)=6xg(x) = \frac{6}{x}:

g(h(x))=g(x2)=6x2.g(h(x)) = g(x^2) = \frac{6}{x^2}.

2. Now, compute (fgh)(x)(f \circ g \circ h)(x):

Substitute g(h(x))=6x2g(h(x)) = \frac{6}{x^2} into f(x)=x+3f(x) = \sqrt{x + 3}:

f(g(h(x)))=f(6x2)=6x2+3.f(g(h(x))) = f\left(\frac{6}{x^2}\right) = \sqrt{\frac{6}{x^2} + 3}.

Thus, the composed function is:

(fgh)(x)=6x2+3.(f \circ g \circ h)(x) = \sqrt{\frac{6}{x^2} + 3}.

Domain:

To determine the domain, we need to consider the restrictions of each function:

  • h(x)=x2h(x) = x^2 is defined for all real xx, (,)(-\infty, \infty).
  • g(x)=6xg(x) = \frac{6}{x} has a restriction that x0x \neq 0.
  • f(x)=x+3f(x) = \sqrt{x+3} requires that x+30x + 3 \geq 0, or x3x \geq -3.

Thus, after combining these conditions, the domain will be restricted by h(x)0h(x) \neq 0, meaning x0x \neq 0. However, since h(x)=x2h(x) = x^2, h(x)h(x) is always non-negative, and the square root function restricts it further.

Therefore, the domain is:

(0,).(0, \infty).

Let me know if you would like further clarifications or detailed explanations!

Follow-up questions:

  1. How is the domain determined in function compositions?
  2. What are the possible cases where the domain of a composed function could be restricted further?
  3. How do you handle square roots in function composition?
  4. Can you explain how the square in h(x)=x2h(x) = x^2 affects the domain of the composition?
  5. Why does g(x)=6xg(x) = \frac{6}{x} cause issues when x=0x = 0?

Tip:

Always evaluate the inner functions first in function composition and ensure the domains align before simplifying the entire expression.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra
Square Root Functions
Rational Functions

Formulas

(f ∘ g ∘ h)(x) = f(g(h(x)))
g(h(x)) = g(x^2) = 6/x^2
f(g(h(x))) = √(6/x^2 + 3)

Theorems

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Suitable Grade Level

Grades 10-12