http://www.mapleprimes.com/questions/43032-Where-Is-The-Problem-In-This-Restricted en-us 2026 Maplesoft, A Division of Waterloo Maple Inc. Maplesoft Document System Thu, 11 Jun 2026 22:54:23 GMT Thu, 11 Jun 2026 22:54:23 GMT The latest answers and comments added to the Question, Where is the problem in this restricted optimization? http://www.mapleprimes.com/images/mapleprimeswhite.jpg http://www.mapleprimes.com/questions/43032-Where-Is-The-Problem-In-This-Restricted http://www.mapleprimes.com/questions/43032-Where-Is-The-Problem-In-This-Restricted?ref=Feed:MaplePrimes:Where is the problem in this restricted optimization?:Comments#answer80039 Hello Jean Jacques, May I suggest that you try your problem using the Student[MultivariateCalculus] package? Study the examples though! Hope that helps. J. Tarr. Hello Jean Jacques, May I suggest that you try your problem using the Student[MultivariateCalculus] package? Study the examples though! Hope that helps. J. Tarr. 80039 Fri, 24 Mar 2006 00:31:22 Z Mariner Mariner http://www.mapleprimes.com/questions/43032-Where-Is-The-Problem-In-This-Restricted?ref=Feed:MaplePrimes:Where is the problem in this restricted optimization?:Comments#answer80018 I think you don't want to differentiate with respect to the Lagrange multiplier. Also, you want things in terms of x, so solve for lambda, y, z rather than x, y, z. Then you get your hand calculated answer: > L:= x*y*z + lambda* (U - (10-x)*(10-y)*(10-z)): > solve( {diff(L, x)=0, diff(L,y)=0, diff(L,z)=0},{lambda,y,z} ); gives {lambda = 0, y = 0, z = 0}, {y = x, lambda = -x^2/(100-20*x+x^2), z = x} Cheers, David. I think you don't want to differentiate with respect to the Lagrange multiplier. Also, you want things in terms of x, so solve for lambda, y, z rather than x, y, z. Then you get your hand calculated answer: > L:= x*y*z + lambda* (U - (10-x)*(10-y)*(10-z)): > solve( {diff(L, x)=0, diff(L,y)=0, diff(L,z)=0},{lambda,y,z} ); gives {lambda = 0, y = 0, z = 0}, {y = x, lambda = -x^2/(100-20*x+x^2), z = x} Cheers, David. 80018 Wed, 29 Mar 2006 10:19:52 Z dharr dharr