Math Problem Statement

find the inverse function of f(x)=2xe^(x)+1

Solution

To find the inverse of the function f(x)=2xex+1f(x) = 2xe^x + 1, we need to follow these steps:

Step 1: Replace f(x)f(x) with yy

y=2xex+1y = 2xe^x + 1 We aim to solve for xx in terms of yy.

Step 2: Isolate 2xex2xe^x

Subtract 1 from both sides: y1=2xexy - 1 = 2xe^x

Step 3: Attempt to solve for xx

This equation involves both xx and exe^x, which is a transcendental equation. It cannot be solved for xx algebraically using elementary functions. However, such equations can sometimes be solved using the Lambert W function, which is the inverse function of xexx e^x.

To express xx in terms of yy, we first try to get the equation into a form that involves the Lambert W function.

Step 4: Rewrite the equation to use the Lambert W function

Divide both sides by 2 to simplify: y12=xex\frac{y - 1}{2} = xe^x

Now, let’s apply the substitution u=xexu = x e^x, so: u=y12u = \frac{y - 1}{2}

Thus, solving for xx, we apply the Lambert W function, denoted as W(z)W(z): x=W(y12)x = W\left(\frac{y - 1}{2}\right)

Final Answer:

The inverse function is: f1(y)=W(y12)f^{-1}(y) = W\left(\frac{y - 1}{2}\right)

The Lambert W function is a special function that generally requires numerical methods or software for evaluation.


Would you like further details on how the Lambert W function works or how to compute specific values for the inverse function?

Here are 5 related questions to explore further:

  1. How can you approximate values of the Lambert W function?
  2. What types of equations can be solved using the Lambert W function?
  3. What is the significance of transcendental equations?
  4. Can the inverse of every function be expressed using elementary functions?
  5. How does the domain of a function affect the existence of an inverse?

Tip: The Lambert W function is widely used to solve equations where a variable appears both as a base and an exponent (e.g., xexx e^x).

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Math Problem Analysis

Mathematical Concepts

Calculus
Transcendental Equations
Inverse Functions
Special Functions

Formulas

f(x) = 2xe^x + 1
Lambert W function: W(z)

Theorems

Lambert W Function

Suitable Grade Level

College Level (Undergraduate)