Math Problem Statement

Determine f(x−1)f(x−1) for the following function.  

f(x)=x−2‾‾‾‾‾√+7

Solution

We are given the function:

f(x)=x2+7f(x) = \sqrt{x - 2} + 7

We are asked to determine f(x1)f(x1)f(x-1) \cdot f(x-1), which is essentially (f(x1))2(f(x-1))^2.

Step 1: Substitute x1x-1 into the function

To find f(x1)f(x-1), substitute x1x-1 for xx in the original function:

f(x1)=(x1)2+7=x3+7f(x-1) = \sqrt{(x-1) - 2} + 7 = \sqrt{x - 3} + 7

Step 2: Square the expression

Now, to compute f(x1)f(x1)f(x-1) \cdot f(x-1), we square the expression for f(x1)f(x-1):

(f(x1))2=(x3+7)2(f(x-1))^2 = \left( \sqrt{x - 3} + 7 \right)^2

Step 3: Expand the square

Use the identity (a+b)2=a2+2ab+b2(a + b)^2 = a^2 + 2ab + b^2 to expand the expression:

(f(x1))2=(x3)2+2x37+72(f(x-1))^2 = \left( \sqrt{x - 3} \right)^2 + 2 \cdot \sqrt{x - 3} \cdot 7 + 7^2

(f(x1))2=(x3)+14x3+49(f(x-1))^2 = (x - 3) + 14 \sqrt{x - 3} + 49

Step 4: Simplify

Combine like terms:

(f(x1))2=x3+49+14x3(f(x-1))^2 = x - 3 + 49 + 14 \sqrt{x - 3}

(f(x1))2=x+46+14x3(f(x-1))^2 = x + 46 + 14 \sqrt{x - 3}

Thus, the expression for f(x1)f(x1)f(x-1) \cdot f(x-1) is:

f(x1)f(x1)=x+46+14x3f(x-1) \cdot f(x-1) = x + 46 + 14 \sqrt{x - 3}

Do you need more details or have any questions?

Here are 5 related questions for deeper understanding:

  1. What is the domain of the function f(x)=x2+7f(x) = \sqrt{x - 2} + 7?
  2. How would f(x2)f(x2)f(x-2) \cdot f(x-2) differ from f(x1)f(x1)f(x-1) \cdot f(x-1)?
  3. Can you find the derivative of f(x)=x2+7f(x) = \sqrt{x - 2} + 7?
  4. How would you determine f1(x)f^{-1}(x), the inverse of f(x)f(x)?
  5. What happens to f(x1)f(x1)f(x-1) \cdot f(x-1) as x3x \to 3?

Tip: When squaring expressions that include square roots, remember to apply the expansion carefully to avoid common mistakes!

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Math Problem Analysis

Mathematical Concepts

Functions
Algebraic Manipulation
Square Roots
Exponents

Formulas

(a + b)^2 = a^2 + 2ab + b^2

Theorems

Properties of square roots and exponents
Function transformation

Suitable Grade Level

Grades 9-11