SIGMOID activation function
Why use the sigmoid function? Because it combines nearly linear behavior, curvilinear behavior, and nearly constant behavior,and nearly constant behavior, depending on the value of the input. Figure 7.3 shows the graph of the sigmoid function y=>>>>>>>>>>> [although f(x) may theoretically take any real - valued input]. through much of the center of the domain of the input x (......), the behavior of f(x) is nearly linear. as the input moves away from the center, f(x) becomes curvilinear. By the time the input reaches extreme value, f(x) becomes nearly constant.