Please help me with this question.
Does anyone know how it ends up with 2 lambda*x transpose*A equal to zero?? I don't understand how the number 2 came up!! Thanks for any help.
As to where the "2" came from, it is essentially from differentiating a square. Or you might prefer to think of it as using the product rule.
Your Lagrangian is . Differentiating , with respect to x, gives and, since , that is the same as .
As a further question in this particular case, I have uploaded an example from my text book which i could not understand the last part of it.
1st pic is connected with the 2nd picture and follow up by the 3rd picture. In particular, I could not understand the whole part of the example in the 3rd pic after finish proving the equation in the 2nd pic. Could you please explain how it works in the 3rd pic. Thank you very much.