Okay kiddo, have you ever seen your mom make a cake and she mixes all sorts of yummy ingredients together like flour, sugar, and eggs? Well, mathematicians also like to mix things together, like numbers, to create new things, and one such thing is the derivative.
Now, imagine your mom put too much sugar in the cake and it became too sweet. She might want to make the cake less sweet by adding other ingredients and adjusting the recipe. In the same way, mathematicians might want to adjust the derivative of a function, and to do that they use something called the gateaux derivative.
The gateaux derivative helps mathematicians adjust the direction and rate of change for a function by comparing it to other functions that are similar. It's like looking at different cake recipes to find the ones that are similar to the one your mom made and adjusting the ingredients based on those similarities.
So overall, the gateaux derivative is like a tool that mathematicians use to adjust the rate and direction of change in a function, similar to how your mom adjusts her cake recipe to make it just right.