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wolfram-mathematicaequalssqrtsimplification

Why Simplify[1/Sqrt[a] == Sqrt[1/a] doesn't give a "true" output in Mathematica?


In Mathematica, Simplify[1/Sqrt[a] == Sqrt[1/a]] gives Sqrt[1/a] == 1/Sqrt[a]. I don't really see why this doesn't give a true output when, FullSimplify gives the desired result.

This probably is a very dumb question, but I just don't see it.


Solution

  • Because if a<0 then sqrt can have complex output values.

    For example

    sqrt(1/-1)=i
    

    while

    1/sqrt(-1)=-i
    

    See wiki.