Math Problem Statement

Let f be a function satisfying ( f(x)=frac{a^{x}}{a^{x}+sqrt{a}}=g_{a}(x)(a>0) )

Solution

Given the function f(x)=axax+af(x) = \frac{a^x}{a^x + \sqrt{a}}, where a>0a > 0, we need to analyze and interpret this function, which is defined as ga(x)g_a(x).

Understanding the Function f(x)f(x):

Let's break down the function step by step.

  1. Definition: The function is given by: f(x)=axax+af(x) = \frac{a^x}{a^x + \sqrt{a}} Here, a>0a > 0 is a constant, and xx is the variable.

  2. Domain: Since axa^x and a\sqrt{a} are well-defined for all real numbers xx, the domain of f(x)f(x) is xRx \in \mathbb{R}.

  3. Behavior at x=0x = 0: f(0)=a0a0+a=11+af(0) = \frac{a^0}{a^0 + \sqrt{a}} = \frac{1}{1 + \sqrt{a}}

  4. Behavior as xx \to \infty: As xx increases, axa^x becomes very large compared to a\sqrt{a}, so: limxf(x)=limxaxax+a=axax(1+aax)=11+0=1\lim_{x \to \infty} f(x) = \lim_{x \to \infty} \frac{a^x}{a^x + \sqrt{a}} = \frac{a^x}{a^x \left(1 + \frac{\sqrt{a}}{a^x}\right)} = \frac{1}{1 + 0} = 1

  5. Behavior as xx \to -\infty: As xx decreases, axa^x becomes very small compared to a\sqrt{a}, so: limxf(x)=limxaxax+a=00+a=0\lim_{x \to -\infty} f(x) = \lim_{x \to -\infty} \frac{a^x}{a^x + \sqrt{a}} = \frac{0}{0 + \sqrt{a}} = 0

Summary of Properties:

  • f(x)f(x) starts from 0 as xx \to -\infty.
  • f(x)f(x) increases and approaches 1 as xx \to \infty.
  • The function is continuous and strictly increasing.

Important Points:

  • Range: The range of f(x)f(x) is (0,1)(0, 1) for all xRx \in \mathbb{R}.
  • Monotonicity: Since f(x)f(x) is increasing, it is a one-to-one function.
  • Derivative: To understand the rate of change, you could compute f(x)f'(x) using the quotient rule.

Would you like to explore the derivative or the inverse of this function, or have any other questions?


Here are 8 related questions to consider:

  1. What is the derivative of f(x)=axax+af(x) = \frac{a^x}{a^x + \sqrt{a}}?
  2. How does the function f(x)f(x) behave if a=1a = 1?
  3. What is the inverse function of f(x)f(x)?
  4. How does the function change if xx is replaced by x-x?
  5. What is the integral of f(x)f(x) over (,)(-\infty, \infty)?
  6. Can you prove that f(x)f(x) is strictly increasing?
  7. What happens to f(x)f(x) when a<1a < 1?
  8. How can you express f(x)f(x) as a composition of simpler functions?

Tip: For functions involving exponential terms, understanding their asymptotic behavior at ±\pm \infty helps to visualize the function's range and limits.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Limits
Asymptotic Behavior

Formulas

Quotient Rule for Differentiation

Theorems

Properties of Exponential Functions

Suitable Grade Level

Advanced High School