Derivatives can be explained in two ways. First of all, according to the Physics concept, derivatives represent the velocity or the speed of an object in its motion, which is the rate of change in distance or displacement divided by time. The other way to explain derivatives is by using a graph of a function. If the function is continuous, then the derivative of the function at a certain point will be equal to the slope of the straight line tangential to the graph. In order to find the slope of the function at point x, we can find the slope of the tangent line at the point (x, f(x)) and the other point (x_0, f(x_0)), which is close to x. When we find the slope of the tangent line, we can get the equation of the line and the derivative of the function at point x at the same time.