MathGroup Archive 2007

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Is this a problem in mathematica?


traz wrote:

>Let's say I wanna solve this problem:
>
>Determine point(s) on y = x^2 +1 that are
>closest to (0,2).
>
>So in mathematica:
>
>minDist = (x - 0)^2 + (y - 2)^2;
>Minimize[minDist, y == 1 + x^2, {x, y}]
>
>Output will give you: x -> -1/Sqrt[2], y -> 3/2
>
>but x also has another answer: +1/Sqrt[2]. Is this a problem in mathematica or can my code be changed to output the other value of x for the minimum distance?
>  
>
Another possibility besides those menioned by others is to use Solve 
once you know the minimum:

minDist=(x-0)^2+(y-2)^2;
Minimize[minDist,y==1+x^2,{x,y}]
{3/4,{x->-1/Sqrt[2],y->3/2}}

Solve[{minDist==3/4,y==1+x^2},{x,y}]
{{y->3/2,x->-1/Sqrt[2]},{y->3/2,x->-1/Sqrt[2]},{y->3/2,x->1/Sqrt[2]},{y->3/2,x->1/Sqrt[2]}}

Carl Woll
Wolfram Research


  • Prev by Date: New to mathematica: Question about solving differential eqs
  • Next by Date: Re: Closing All Input Cells at Once
  • Previous by thread: Re: Is this a problem in mathematica?
  • Next by thread: Re: Is this a problem in mathematica?