Let a given binary function z=? (x, y) and the additional condition φ(x, y)=0, in order to find z=? For the extreme point of (x, y) under additional conditions, the Lagrange function L(x, y)=? (x, y)+λφ(x, y), where λ is the parameter. Find the first partial derivative of L(x, y) to x, y to make it equal to zero, and combine with additional conditions, namely

L'x(x，y)=？ x(x，y)+λφ’x(x，y)=0，

L'y(x，y)=？ y(x，y)+λφ'y(x，y)=0，

φ(x，y)=0

Solve x, y, λ from the above equation, and the (x, y) thus obtained is the function z=? Possible extreme points of (x, y) under the additional condition φ(x, y)=0.

The known additional condition is 8X+ 10Y=200.

L(X，Y)=lnX+lnY+ in (8X+ 10Y-200)

Then later, according to the above calculation,

The calculation result must be decimal, so the integer solution must be considered.

For example, you get 12.8 and 7.8. You have to calculate which is bigger, L (12,8) or L (13,7).

I mean your answer to this question ... look at the last two lines by yourself, which obviously doesn't equal 200. Say it backwards.

The topic is also a mess, buy X disk and Y disk, like the following …

Hey, what a terrible topic!