How does the loss function work?

Question

Mathematics

How does the cost and loss function work? I need for logistic regression. I searched on google but didn't find anything. I ask who knows help and explain with simple breaks

ps. In my example, I am trying to find a cat in an image.

I was given in my example ŷ(my probability is from 1 to 0 according to the formula on which the sigmoid ( w * x + b ) and (y) were also applied (from the training data set)

Answer 1

The loss function calculates the error between the estimated and the true result. The idea is that you can't just subtract one from the other, sometimes it's impossible. Therefore, a number is calculated that characterizes the correctness of the result.