Why is the height of J(w) at the left, negative 2, but the right height of J(w) is positive 2? why the left height and right height of J(w) is the same?
Hi @Wu_Wei
welcome to our community!
In the image above…the derivative of the left side is negative because when we get the tangent line of the cost function and get the derivative of it according to this equation
or tan of the angle the value is negative, and vice versa in the other part
Best Regards,
Abdelrahman