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Re: Q: Solve gives complex solution where there is a noncomplex solution how to get the last one?
On 26 Aug 2004, at 19:50, Dick Barends wrote: > *This message was transferred with a trial version of CommuniGate(tm) > Pro* > Hello, > > The following line > > Solve[x y / ( 1 + y^2 )^0.5 == a, y] > > Gives a complex solution : (0.+ i )a / (a^2 - x^2)^0.5 > Which is correct but could be simpler, not complex > > The solution I expected is: a/(x^2 - a^2)^0.5 > > How can I instruct Mathematica (Solve) to give the simple solution > directly. > > kind regards > Dick Barends > > > Use Solve[x y / ( 1 + y^2 )^(1/2) == a, y] In Mathematica 0.5 and 1/2 are quite different entities and you should not use them interchangeably. If you really mean the square root you should always use the power 1/2. Andrzej Kozlowski