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FindRoot - "only some of the components are equations" error

Anonymous User
Anonymous User
Posted 9 years ago

Hello guys! An attempt to solve

 FindRoot[{0.8*p*((y^0.2)?(x^0.2))+x ((x-2))?((x-1)^2)==0,0.2*p*((x^0.8)?(y^0.8))+y ((y-2))?((y-1)^2)==0,0.8*p*((y1^0.2)?(x1^0.2))+x1 ((x1-4))?((x1-2)^2)==0,0.2*p*((x1^0.8)?(y1^0.8))+y1 ((y1-4))?((y1-2)^2)==0,6*p^-2==x^0.8y^0.2+x1^0.8y1^0.2,0?x?0.999,0?y?0.999,0?x1?1.999,0?y1?1.999,0?p},{{x,0.1},{y,0.1},{x1,0.1},{y1,0.1},{p,0.1}}]

has brought to:

In the first argument 
{((-2+x) x)/(-1+x)2+(0.8 p y0.2)/x0.2==0,(0.2 p x0.8)/y0.8+((-2+y) y)/(-1+y)2==0,((-4+x1) x1)/(-2+x1)2+(0.8 p y10.2)/x10.2==0,(0.2 p x10.8)/y10.8+((-4+y1) y1)/(-2+y1)2==0,6/p2==x0.8 y0.2+x10.8 y10.2,0<=x<=0.999,0<=y<=0.999,0<=x1<=1.999,0<=y1<=1.999,0<=p} 
only some of the components are equations. >>

Yet, Excel straight returns solution {0.393085,0.236113,0.786171,0.472226,2.373604}. I need your help to understand whatÂ’s wrong with it.

POSTED BY: Anonymous User

Remove the inequalities, which are not accepted by FindRoot:

FindRoot[{0.8 p ((y^0.2)/(x^0.2)) + x ((x - 2))/((x - 1)^2) == 0, 
  0.2 p ((x^0.8)/(y^0.8)) + y ((y - 2))/((y - 1)^2) == 0, 
  0.8 p ((y1^0.2)/(x1^0.2)) + x1 ((x1 - 4))/((x1 - 2)^2) == 0, 
  0.2 p ((x1^0.8)/(y1^0.8)) + y1 ((y1 - 4))/((y1 - 2)^2) == 0, 
  6*p^-2 == x^0.8 y^0.2 + x1^0.8 y1^0.2}, {{x, 0.1}, {y, 0.1}, {x1, 
   0.1}, {y1, 0.1}, {p, 0.1}}]
POSTED BY: Gianluca Gorni
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