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 Author Comment/Response Daniele Lupo 10/04/05 5:57pm Hi to all. I've a problem with the derivative of Abs. Considering, for example, this function a = Abs[Sqrt[s + x]] If (with mathematica 5.1), I use this command D[a, x] I obtain this Derivative[1][Abs][s + x]/(2*Sqrt[Abs[s + x]]) It containts Abs'[..] that's not right. If I use PiecewiseExpand in this way PiecewiseExpand[a] I don't obtain nothing, while in this way PiecewiseExpand[a, Reals] I obtain Piecewise[{{Sqrt[-s - x], s + x < 0}}, Sqrt[s + x]] But In this case I consider all variables as real. Instead I want that x is real, while s is complex, and making an expansion with these assumptions. How can I do it? Thanks for answers Daniele URL: ,

 Subject (listing for 'Problem with Abs and D') Author Date Posted Problem with Abs and D Daniele Lupo 10/04/05 5:57pm Re: Problem with Abs and D Forum Modera... 11/23/05 1:48pm Re: Problem with Abs and D Peter Pein 11/23/05 8:57pm
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