Name: Sun Qingfeng Date: 09/13/15-08:41:09 AM Z


Several Months ago, I find a problem in the “Calc” function.

Now, In the new version of FC9.0 with mathematica 10.1, a similar problem appears again:

$Assumptions = {x > 1}

Sqrt[x - 1] // Calc

and the output looks like:

I Sqrt[1-x] exp(I \[Pi] \[LeftFloor]-(arg(1-x)/(2 \[Pi]))\[RightFloor]+9 I \[Pi] \[LeftFloor]1/2-arg(1-x)/(2 \[Pi])\[RightFloor])

But I think the expected output should be:
Sqrt[x - 1]