Lambert W Function: Solving Y=xe^(x^2)

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In summary, the Lambert W function is a special function in mathematics that is defined as the inverse of the exponential function. It is useful in solving equations and problems involving the exponential function and is used in various fields. To solve an equation using the Lambert W function, one can take the natural logarithm of both sides and use the definition of the function to rewrite the equation. However, it has some limitations such as being only defined for certain values and having multiple solutions for a given value. It can be used for both real and complex numbers but choosing the appropriate branch is important when dealing with complex numbers.
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Nandan_78
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Dear scholars,

I am working on the following equation and wonder whether my solution is correct. The actual problem is more complex but the example below captures the main features. I have not a lot of experience with the Lambert W function. Thanks in advance for your comments!

Equation:
$$Y=x \exp(x^2)$$

Substitute: $$u=x^2$$

Then:
$$Y=\sqrt{u} \exp(u)$$
$$Y^2=u \exp(2u)$$
$$2Y^2=2u \exp(2u)$$

Then using W function:
$$2u=W(2Y^2)$$
From which $$x$$ follows.
 
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Correct.
 
  • #3
Yes, very good!
 

1. What is the Lambert W function?

The Lambert W function, denoted by W(x), is a special function in mathematics that is defined as the inverse of the function f(x)=xe^x. In other words, it is the solution to the equation W(x)e^W(x)=x.

2. Why is the Lambert W function useful?

The Lambert W function is useful in solving equations and problems that involve the exponential function, particularly when the variable appears both inside and outside of the exponential. It is also used in various areas of mathematics, physics, and engineering.

3. How do you solve an equation using the Lambert W function?

To solve an equation in the form of y=xe^(x^2), you can use the Lambert W function by taking the natural logarithm of both sides, resulting in ln(y)=x^2+ln(x). Then, use the definition of the Lambert W function to rewrite the equation as x=W(ln(y)), giving you the solution for x.

4. Are there any limitations to using the Lambert W function?

Yes, the Lambert W function has some limitations. It is only defined for values of x≥-1/e and it is a multivalued function, meaning that for a given value of x, there can be multiple solutions for W(x). Additionally, it may not have a closed-form solution for certain equations.

5. Can the Lambert W function be used for real and complex numbers?

Yes, the Lambert W function can be used for both real and complex numbers. However, when dealing with complex numbers, the function may have multiple branches and choosing the appropriate branch is important for obtaining the correct solution.

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