ELI5: Explain Like I'm 5

Lambert W function

The Lambert W function is like a magic calculator that can solve equations that involve a variable in the exponent but also appear in other places. Imagine you have a complicated equation that looks like this:

x^2 + 3x - 4 = 0

You could use the quadratic formula to solve this equation and find the values of x that make it true. But what if you have an equation like this:

x^2 + 2x = 2^x

This equation is much more complicated because x appears in both the exponent and the base. Without the Lambert W function, it would be almost impossible to solve for x!

The Lambert W function can help you solve equations like this by giving you a way to express the variable in terms of other variables that you can solve for. For example, if we use the Lambert W function to solve the equation above, we can rewrite it as:

x = W(2^x-1)

This equation may look just as complicated as the original one, but it's actually much simpler because we can now use the Lambert W function to find the value of x. Essentially, the function tells us what value we would have to raise e (the mathematical constant approximately equal to 2.718) to in order to get 2^x-1.

The Lambert W function may seem like magic, but it's actually based on some pretty advanced math. It's named after Johann Lambert, an 18th-century mathematician who first discovered it while studying the properties of the exponential function. Today, it's used in a wide range of fields, from physics and engineering to economics and finance.