What are derivatives and why do derivatives exist?

Answer 1

The derivative of a function is another function that represents the slope of the function at each of the points in the original function's domain.

For instance, given the function f(x) = x2, the derivative is f'(x) = 2x. This says that the slope of the original function f(x) = x2 is 2x at every x. This is very useful when you want to graph the function, because you only need a few data points, and then you can quickly sketch the shape of the curve when you know the slope.

Later on, you are going to learn about anti-derivatives, and you are going to call them integrals, and you are going to learn the vast power of this thing we call calculus in terms of finding the area under a curve, but let's take it one step at a time.