ELI5: Explain Like I'm 5

Steffensen's method

Steffensen's method is like playing a guessing game to find the answer to a question. Imagine that you are trying to guess a number that someone is thinking of. You ask them if the number is bigger or smaller than a certain guess you make. Depending on their answer, you make a new guess that is either higher or lower until you get closer and closer to the right answer.

In Steffensen's method, instead of guessing a number, we are trying to find the root of a function. A root is a number that, when plugged into the function, makes it equal to zero. We start with an initial guess for the root, and then use that guess to make a better one. How do we do that?

First, we evaluate the function at the initial guess to see if we are too high or too low. If we are too high, we need to make a lower guess. If we are too low, we need to make a higher guess. This is like the bigger or smaller guessing game.

Next, we use the new guess to evaluate the function again, and this time we see how much we have improved. If we are still not close enough to the root, we repeat the process: use our current guess to evaluate the function and then use that information to make a better guess. Keep in mind that the ultimate goal is to find a root of the function.

Steffensen's method is useful because it can find roots more quickly than some other methods. However, it requires some knowledge of calculus and can be more complicated than other methods for some functions. But, in the end, it can be a useful tool for finding the solutions to many problems.