Math Problem Statement

Show that f(x) = 9x^{-1/2} + Ax^{1/2} + B, where A and B are constants to be found.

Solution

To show that f(x)=9x12+Ax12+Bf(x) = 9x^{-\frac{1}{2}} + Ax^{\frac{1}{2}} + B, let's start with the given function and simplify it.

Given:

f(x)=(34x)2x,x>0f(x) = \frac{\left(3 - 4\sqrt{x}\right)^2}{\sqrt{x}}, \quad x > 0

Step 1: Expand the Numerator

The numerator (34x)2(3 - 4\sqrt{x})^2 can be expanded using the formula (ab)2=a22ab+b2(a - b)^2 = a^2 - 2ab + b^2: (34x)2=32234x+(4x)2(3 - 4\sqrt{x})^2 = 3^2 - 2 \cdot 3 \cdot 4\sqrt{x} + (4\sqrt{x})^2 =924x+16x= 9 - 24\sqrt{x} + 16x

So, the function f(x)f(x) becomes: f(x)=924x+16xxf(x) = \frac{9 - 24\sqrt{x} + 16x}{\sqrt{x}}

Step 2: Separate Terms in the Numerator

Now, divide each term in the numerator by x\sqrt{x}: f(x)=9x24xx+16xxf(x) = \frac{9}{\sqrt{x}} - \frac{24\sqrt{x}}{\sqrt{x}} + \frac{16x}{\sqrt{x}}

This simplifies each term as follows:

  • 9x=9x12\frac{9}{\sqrt{x}} = 9x^{-\frac{1}{2}}
  • 24xx=24\frac{24\sqrt{x}}{\sqrt{x}} = 24
  • 16xx=16x12\frac{16x}{\sqrt{x}} = 16x^{\frac{1}{2}}

Thus: f(x)=9x12+16x1224f(x) = 9x^{-\frac{1}{2}} + 16x^{\frac{1}{2}} - 24

Step 3: Compare with the Desired Form

We have: f(x)=9x12+16x1224f(x) = 9x^{-\frac{1}{2}} + 16x^{\frac{1}{2}} - 24

This matches the form f(x)=9x12+Ax12+Bf(x) = 9x^{-\frac{1}{2}} + Ax^{\frac{1}{2}} + B, where:

  • A=16A = 16
  • B=24B = -24

Final Answer:

A=16,B=24A = 16, \quad B = -24

Would you like further details on any of the steps?

Here are some related questions:

  1. How can we determine the behavior of f(x)f(x) as x0x \to 0 or xx \to \infty?
  2. What would the derivative f(x)f'(x) of this function look like?
  3. How does the presence of x12x^{-\frac{1}{2}} affect the domain of f(x)f(x)?
  4. Can we integrate f(x)f(x) over a specific interval?
  5. How would the graph of f(x)=9x12+16x1224f(x) = 9x^{-\frac{1}{2}} + 16x^{\frac{1}{2}} - 24 appear?

Tip: When simplifying expressions with roots or powers, look for ways to separate terms by division to simplify the overall structure of the expression.

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Math Problem Analysis

Mathematical Concepts

Algebra
Simplification of Expressions
Radicals and Exponents

Formulas

(a - b)^2 = a^2 - 2ab + b^2
f(x) = (3 - 4√x)^2 / √x

Theorems

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Suitable Grade Level

Undergraduate or Advanced High School Level