Author 
Comment/Response 
Hettie

08/23/12 08:39am
I have a problem with Findroot. When I try to find the (second) root of a parabolic function, for example:
X^25x+a, I plot:
Root2[a_]:=Re[(x /. FindRoot[x^25x+a==0,{x,10, 0,10}])]
However, when parameter 'a' increases, I know from the plot of this function, that there does not exist a root. But Mathematica still gives a solution. This solution is then the minimum of this parabolic function (and thus not a root).
Can anyone help me? I want to find a root, only if there is a root, and otherwise I want that mathematica tells me somehow, that there is no root. I allready tried to make it into an iffunction. This works, however, I have a big mfile that uses a findrootfunction into another findroot function etc. So my program becomes really slow if I have to make a lot of iffunctions.
Maybe is there another code that I can use?
Thanks,
Greets!
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